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# ABC problem

ABC problem
You are encouraged to solve this task according to the task description, using any language you may know.

You are given a collection of ABC blocks   (maybe like the ones you had when you were a kid).

There are twenty blocks with two letters on each block.

A complete alphabet is guaranteed amongst all sides of the blocks.

The sample collection of blocks:

(B O)
(X K)
(D Q)
(C P)
(N A)
(G T)
(R E)
(T G)
(Q D)
(F S)
(J W)
(H U)
(V I)
(A N)
(O B)
(E R)
(F S)
(L Y)
(P C)
(Z M)

Write a function that takes a string (word) and determines whether the word can be spelled with the given collection of blocks.

The rules are simple:

1.   Once a letter on a block is used that block cannot be used again
2.   The function should be case-insensitive
3.   Show the output on this page for the following 7 words in the following example

Example
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True

## 11l

Translation of: Python
F can_make_word(word)
I word == ‘’
R 0B

V blocks_remaining = ‘BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM’.split(‘ ’)

L(ch) word.uppercase()
L(block) blocks_remaining
I ch C block
blocks_remaining.remove(block)
L.break
L.was_no_break
R 0B
R 1B

print([‘’, ‘a’, ‘baRk’, ‘booK’, ‘treat’, ‘COMMON’, ‘squad’, ‘Confused’].map(w -> ‘'’w‘': ’can_make_word(w)).join(‘, ’))

## 360 Assembly

The program uses one ASSIST macro (XPRNT) to keep the code as short as possible.

*        ABC Problem               21/07/2016
ABC CSECT
USING ABC,R13 base register
B 72(R15) skip savearea
DC 17F'0' savearea
STM R14,R12,12(R13) prolog
ST R13,4(R15) " <-
ST R15,8(R13) " ->
LR R13,R15 " addressability
LA R8,1 l=1
LOOPL C R8,=A(NN) do l=1 to hbound(words)
BH ELOOPL
LR R1,R8 l
MH R1,=H'20' *20
LA R10,WORDS-20(R1) @words(l)
MVC STATUS,=CL5'true' cflag='true'
MVC TBLOCKS,BLOCKS tblocks=blocks
MVC CC(1),0(R10) cc=substr(words(l),1,1)
LA R6,1 i=1
LOOPI CLI CC,C' ' do while cc<>' '
BE ELOOPI
SR R7,R7 k=0
LH R0,=H'1' m=1
LOOPM CH R0,=AL2(L'TBLOCKS) do m=1 to length(tblocks)
BH ELOOPM
LA R5,TBLOCKS-1 @tblocks[0]
AR R5,R0 @tblocks[m]
CLC 0(1,R5),CC if substr(tblocks,m,1)=cc
BNE INDEXM
LR R7,R0 k=m=index(tblocks,cc)
B ELOOPM
INDEXM AH R0,=H'1' m=m+1
B LOOPM
ELOOPM LTR R7,R7 if k=0
BNZ OKK
MVC STATUS,=CL5'false' cflag='false'
B EIFK0
OKK LA R4,TBLOCKS-2 @tblocks[-1]
AR R4,R7 +k
CLI 0(R4),C'(' if substr(tblocks,k-1,1)='('
BNE SECOND
LA R0,1 j=1
B EIFBLOCK
SECOND LA R0,3 j=3
EIFBLOCK LR R2,R7 k
SR R2,R0 k-j
LA R4,TBLOCKS-1 @tblocks[0]
AR R4,R2 @tblocks[k-j]
MVC 0(5,R4),=CL5' ' substr(tblocks,k-j,5)=' '
EIFK0 LA R6,1(R6) i=i+1
LR R4,R10 @words
AR R4,R6 +i
BCTR R4,0 -1
MVC CC,0(R4) cc=substr(words,i,1)
B LOOPI
ELOOPI MVC PG(20),0(R10) tabword(l)
MVC PG+20(5),STATUS status
XPRNT PG,80 print buffer
LA R8,1(R8) l=l+1
B LOOPL
ELOOPL L R13,4(0,R13) epilog
LM R14,R12,12(R13) " restore
XR R15,R15 " rc=0
BR R14 exit
WORDS DC CL20'A',CL20'BARK',CL20'BOOK',CL20'TREAT',CL20'COMMON'
BLOCKS DS 0CL122
DC CL61'((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G) (Q D) (F S) '
DC CL61'(J W) (H U) (V I) (A N) (O B) (E R) (F S) (L Y) (P C) (Z M)) '
TBLOCKS DS CL(L'BLOCKS) work blocks
CC DS CL1 letter to find
STATUS DS CL5 true/false
PG DC CL80' ' buffer
YREGS
NN EQU (BLOCKS-WORDS)/L'WORDS number of words
END ABC
Output:
A                   true
BARK                true
BOOK                false
TREAT               true
COMMON              false
CONFUSE             true

## 8080 Assembly

org	100h
jmp test
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Subroutine 'blocks': takes a \$-terminated string in
;;; DE containing a word, and checks whether it can be
;;; written with the blocks.
;;; Returns: carry flag set if word is accepted.
;;; Uses registers: A, B, D, E, H, L
blocks: push d ; Store string pointer
lxi h,blockslist ; At the start, all blocks are
lxi d,blocksavail ; available
mvi b,40
blocksinit: mov a,m
stax d
inx h
inx d
dcr b
jnz blocksinit
pop d ; Restore string pointer
blockschar: ldax d ; Get current character
cpi '\$' ; End of string?
stc ; Set carry flag (accept string)
rz ; And then we're done
ani 0DFh ; Make uppercase
lxi h,blocksavail ; Is it available?
mvi b,40
blockscheck: cmp m
jz blocksaccept ; Yes, we found it
inx h ; Try next available char
dcr b
jnz blockscheck
ana a ; Char unavailable, clear
ret ; carry and stop.
blocksaccept: mvi m,0 ; We've now used this char
mov a,l ; And its blockmate
xri 1
mov l,a
mvi m,0
inx d ; Try next char in string
jmp blockschar
;; Note: 'blocksavail' must not cross page boundary
blockslist: db 'BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM'
blocksavail: ds 40
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Test code: run the subroutine on the given words.
test: lxi h,words
doword: mov e,m ; Get pointer to next word
inx h
mov d,m
inx h
mov a,e ; If zero, end of word list
ora d
rz
push h ; Save pointer to list
push d ; Save pointer to word
mvi c,9 ; Write word to console
call 5
pop d ; Retrieve word ponter
call blocks ; Run the 'blocks' routine
lxi d,yes ; Say 'yes',
jc yesno ; if the carry is set.
lxi d,no ; Otherwise, say 'no'.
yesno: mvi c,9
call 5
pop h ; Restore list pointer
jmp doword ; Do next word
yes: db ': Yes',13,10,'\$'
no: db ': No',13,10,'\$'
words: dw wrda,wrdbark,wrdbook,wrdtreat,wrdcommon
wrda: db 'A\$'
wrdbark: db 'BARK\$'
wrdbook: db 'BOOK\$'
wrdtreat: db 'TREAT\$'
wrdcommon: db 'COMMON\$'
wrdconfuse: db 'CONFUSE\$'
Output:
A>blocks
A: Yes
BARK: Yes
BOOK: No
TREAT: Yes
COMMON: No
CONFUSE: Yes

## 8086 Assembly

Translation of: 8080 Assembly
cpu	8086
bits 16
org 100h
section .text
jmp demo
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Subroutine "blocks": see if the \$-terminated string in DS:BX
;;; can be written with the blocks.
;;; Returns: carry flag set if word is accepted.
;;; Uses registers: AL, BX, CX, SI, DI
;;; Assumes CS=DS=ES
blocks: mov si,.list ; Set all blocks available
mov di,.avail
mov cx,20
rep movsw
.char: mov al,[bx] ; Get current character
inc bx
cmp al,'\$' ; Are we at the end?
je .ok ; Then the string is accepted
mov cx,40 ; If not, check if block is available
mov di,.avail
repne scasb
test cx,cx ; This clears the carry flag
jz .out ; If zero, block is not available
dec di ; Zero out the block we found
mov [di],ch ; CH is guaranteed 0 here
xor di,1 ; Point at other character on block
mov [di],ch ; Zero out that one too.
jmp .char
.ok: stc
.out: ret
.list: db 'BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM'
.avail: db ' '
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Test code: run the subroutine on the given words
demo: mov bp,words
wrd: mov dx,[bp] ; Get word
test dx,dx ; End of words?
jz stop
mov ah,9 ; Print word
int 21h
mov bx,dx ; Run subroutine
call blocks
mov dx,yes ; Print yes or no depending on carry
jc print
mov dx,no
print: mov ah,9
int 21h
inc bp
inc bp
jmp wrd
stop: ret
section .data
yes: db ': Yes',13,10,'\$'
no: db ': No',13,10,'\$'
.a: db 'A\$'
.bark: db 'BARK\$'
.book: db 'BOOK\$'
.treat: db 'TREAT\$'
.cmn: db 'COMMON\$'
.confs: db 'CONFUSE\$'
Output:
A: Yes
BARK: Yes
BOOK: No
TREAT: Yes
COMMON: No
CONFUSE: Yes

## 8th

\ ========================================================================================
\ You are given a collection of ABC blocks
\ There are twenty blocks with two letters on each block.
\ A complete alphabet is guaranteed amongst all sides of the blocks.
\
\ Write a function that takes a string (word) and determines whether
\ the word can be spelled with the given collection of blocks.
\
\ Rules:
\ 1. Once a letter on a block is used that block cannot be used again
\ 2. The function should be case-insensitive
\ 3. Show the output on this page for the following 7 words in the following example
\ can_make_word(???) where ??? is resp.:
\ "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"
\
\ NOTE:
\ to make the program readable for even n00bs, I have a comment at the end of each line.
\ The comments take the form of:
\ \ <stack> | <rstack>
\ in order to be able to follow exactly what the program does.
\ ========================================================================================

["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS","JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"] var, blks
["a", "AbBa", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"] var, chkwrds

needs stack/rstack

a:new var, paths \ Keeps the combinatory explosion of letter paths
var wrd
var success
var ix

: uni2char "" swap s:+ ;

: char2uni 0 s:@ nip ;

: rreset rstack st:clear drop ;

: addoneletter \ ix path -- \ ix path | letter
[email protected] \ ix path letter | letter
s:+ \ ix newpath | letter
paths @ \ ix newpath paths | letter
-rot \ paths ix newval | letter
a:! \ paths | letter
drop \ | letter
;

: oneletter \ letter -- \ letter
>r \ | letter
paths @ ' addoneletter a:each drop \ | letter
;

: addtwoletters \ ix path -- \ ix path | letter1 letter2 halflen
swap \ path ix | letter1 letter2 halflen
dup \ path ix ix | letter1 letter2 halflen
[email protected] \ path ix ix halflen | letter1 letter2 halflen
n:< \ path ix bool | letter1 letter2 halflen
if \ path ix | letter1 letter2 halflen
swap \ ix path | letter1 letter2 halflen
1 rpick \ ix path letter | letter1 letter2 halflen
else
swap \ ix path | letter1 letter2 halflen
2 rpick \ ix path letter | letter1 letter2 halflen
then
s:+ \ ix newpath | letter1 letter2 halflen
paths @ \ ix newpath paths | letter1 letter2 halflen
-rot \ paths ix newpath | letter1 letter2 halflen
a:! \ paths | letter1 letter2 halflen
drop \ | letter1 letter2 halflen
;

: twoletters \ letters -- \ letters
\ fetch the 2 letters
dup \ letters letters
1 s:lsub \ letters letter1
>r \ letters | letter1
1 s:rsub \ letter2 | letter1
>r \ | letter1 letter2
\ duplicate paths in itself
paths @ dup a:+ \ paths | letter1 letter2
\ halfway length of array
a:len \ paths len | letter1 letter2
2 / \ paths halflen | letter1 letter2
>r \ paths | letter1 letter2 halflen
\ add letters to paths
' addtwoletters a:each drop \ | letter1 letter2 halflen
rreset \
;

: chkletter \ letter -- letter \ letter
dup \ letter letter
wrd @ \ letter letter word
swap uni2char \ letter word letter
s:search \ letter word index
null? \ letter word index bool
nip \ letter word bool
if \ letter word
2drop \
"" \ letter
else \ letter word
drop \ letter
then \
;

: buildpaths \ ix blk -- \ ix blk
nip \ blk
' chkletter s:map \ resultletters
s:len \ resultletters len
dup \ resultletters len len
0 \ resultletters len len 0
n:= \ resultletters len bool
if \ resultletters len
\ This block contains no letters of current word
2drop \
;; \ exit word
then \ resultletters len
1 \ resultletters len 1
n:= \ resultletters bool
if \ resultletters
oneletter \
else \ resultletters
twoletters \
then
;

: chkokpath \ ix wrdch -- \ ix wrdch | path
swap \ wrdch ix | path
ix ! \ wrdch | path
[email protected] \ wrdch path | path
dup \ wrdch path path | path
"" \ wrdch path path "" | path
s:= \ wrdch path bool | path
if \ wrdch path | path
\ Path is empty - no match
2drop \ | path
break \ | path
;; \ | path
then
swap \ path wrdch | path
uni2char \ path wrdch | path
s:search \ path pos | path
null? \ path pos bool | path
if \ path pos | path
\ Letter not found in path - no match
2drop \ | path
break \ | path
else \ path pos | path
wrd @ \ path pos wrd | path
s:len \ path pos wrd len | path
nip \ path pos len | path
n:1- \ path pos cix | path
ix @ \ path pos cix ix | path
n:= \ path pos bool | path
if \ path pos | path
\ We have a match!
true success ! \ path pos | path
2drop \ | path
break \ | path
else \ path pos | path
1 \ path pos len | path
s:- \ restpath | path
rdrop >r \ | restpath
then
then
;

: chkpath \ ix path -- \ ix path
nip \ path
>r \ | path
wrd @ \ wrd | path
' chkokpath s:each \ | path
rdrop \
success @ \ success
if \
break \
then
;

: chkwrd \ ix wrd -- \ ix wrd
nip \ wrd
s:uc \ wrdupper
"Word=" . dup . \ wrdupper
wrd ! \
\ other word - clear paths
paths @ a:clear "" a:push drop \
\ create path tree for this word
blks @ ' buildpaths a:each drop \
\ check if word can be made from a path
false success ! \
paths @ ' chkpath a:each drop \
success @ \ success
"\t\t" . . cr \
;

: app:main
chkwrds @ ' chkwrd a:each drop \ check if word can be made
bye
;

## AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits

/* ARM assembly AARCH64 Raspberry PI 3B */
/* program problemABC64.s */

/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ TRUE, 1
.equ FALSE, 0

/*********************************/
/* Initialized data */
/*********************************/
.data
szMessTitre1: .asciz "Can_make_word: @ \n"
szMessTrue: .asciz "True.\n"
szMessFalse: .asciz "False.\n"
szCarriageReturn: .asciz "\n"

szTablBloc: .asciz "BO"
.asciz "XK"
.asciz "DQ"
.asciz "CP"
.asciz "NA"
.asciz "GT"
.asciz "RE"
.asciz "TG"
.asciz "QD"
.asciz "FS"
.asciz "JW"
.asciz "HU"
.asciz "VI"
.asciz "AN"
.asciz "OB"
.asciz "ER"
.asciz "FS"
.asciz "LY"
.asciz "PC"
.asciz "ZM"
.equ NBBLOC, (. - szTablBloc) / 3

szWord1: .asciz "A"
szWord2: .asciz "BARK"
szWord3: .asciz "BOOK"
szWord4: .asciz "TREAT"
szWord5: .asciz "COMMON"
szWord7: .asciz "CONFUSE"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
.align 4
qtabTopBloc: .skip 8 * NBBLOC
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
bl traitBlock // control word

bl traitBlock // control word

bl traitBlock // control word

bl traitBlock // control word

bl traitBlock // control word

bl traitBlock // control word

bl traitBlock // control word

100: // standard end of the program
mov x0, #0 // return code
mov x8, #EXIT // request to exit program
svc #0 // perform the system call

/******************************************************************/
/* traitement */
/******************************************************************/
/* x0 contains word */
traitBlock:
stp x1,lr,[sp,-16]! // save registres
mov x1,x0
ldr x0,qAdrszMessTitre1 // insertion word in message
bl strInsertAtCharInc
bl affichageMess // display title message
mov x0,x1
bl controlBlock // control
cmp x0,#TRUE // ok ?
bne 1f
ldr x0,qAdrszMessTrue // yes
bl affichageMess
b 100f
1: // no
bl affichageMess
100:
ldp x1,lr,[sp],16 // restaur des 2 registres
ret
/******************************************************************/
/* control if letters are in block */
/******************************************************************/
/* x0 contains word */
controlBlock:
stp x1,lr,[sp,-16]! // save registres
stp x2,x3,[sp,-16]! // save registres
stp x4,x5,[sp,-16]! // save registres
stp x6,x7,[sp,-16]! // save registres
stp x8,x9,[sp,-16]! // save registres
mov x5,x0 // save word address
mov x2,#0
mov x3,#0
1: // init table top block used
str x3,[x4,x2,lsl #3]
cmp x2,#NBBLOC
blt 1b
mov x2,#0
2: // loop to load letters
ldrb w3,[x5,x2]
cbz w3,10f // end
mov x0,0xDF
and x3,x3,x0 // transform in capital letter
mov x8,#0
3: // begin loop control block
ldr x7,[x4,x8,lsl #3] // block already used ?
cbnz x7,5f // yes
add x9,x8,x8,lsl #1 // no -> index * 3
ldrb w7,[x6,x9] // first block letter
cmp w3,w7 // equal ?
beq 4f
ldrb w7,[x6,x9] // second block letter
cmp w3,w7 // equal ?
beq 4f
b 5f
4:
mov x7,#1 // top block
str x7,[x4,x8,lsl #3] // block used
b 2b // next letter
5:
cmp x8,#NBBLOC
blt 3b
mov x0,#FALSE // no letter find on block -> false
b 100f
10: // all letters are ok
mov x0,#TRUE
100:
ldp x8,x9,[sp],16 // restaur des 2 registres
ldp x6,x7,[sp],16 // restaur des 2 registres
ldp x4,x5,[sp],16 // restaur des 2 registres
ldp x2,x3,[sp],16 // restaur des 2 registres
ldp x1,lr,[sp],16 // restaur des 2 registres
ret
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"

Output:
Can_make_word: A
True.
Can_make_word: BARK
True.
Can_make_word: BOOK
False.
Can_make_word: TREAT
True.
Can_make_word: COMMON
False.
True.
Can_make_word: CONFUSE
True.

## ABAP

REPORT z_rosetta_abc.

" Type declaration for blocks of letters
TYPES: BEGIN OF block,
s1 TYPE char1,
s2 TYPE char1,
END OF block,

blocks_table TYPE STANDARD TABLE OF block.

DATA: blocks TYPE blocks_table.

CLASS word_maker DEFINITION.
PUBLIC SECTION.
CLASS-METHODS:
can_make_word
IMPORTING word TYPE string
letter_blocks TYPE blocks_table
RETURNING VALUE(found) TYPE abap_bool.
ENDCLASS.

CLASS word_maker IMPLEMENTATION.
METHOD can_make_word.

" Create a reader stream that reads 1 character at a time

DATA(blocks) = letter_blocks.

DATA(ch) = to_upper( reader->read( 1 ) ).
found = abap_false.

LOOP AT blocks REFERENCE INTO DATA(b).
IF ch = b->s1 OR ch = b->s2.
found = abap_true.
DELETE blocks INDEX sy-tabix.
EXIT. " the inner loop once a character is found
ENDIF.
ENDLOOP.

" If a character could not be found, stop looking further
IF found = abap_false.
RETURN.
ENDIF.
ENDWHILE.

ENDMETHOD.
ENDCLASS.

START-OF-SELECTION.

blocks = VALUE #( ( s1 = 'B' s2 = 'O' ) ( s1 = 'X' s2 = 'K' )
( s1 = 'D' s2 = 'Q' ) ( s1 = 'C' s2 = 'P' )
( s1 = 'N' s2 = 'A' ) ( s1 = 'G' s2 = 'T' )
( s1 = 'R' s2 = 'E' ) ( s1 = 'T' s2 = 'G' )
( s1 = 'Q' s2 = 'D' ) ( s1 = 'F' s2 = 'S' )
( s1 = 'J' s2 = 'W' ) ( s1 = 'H' s2 = 'U' )
( s1 = 'V' s2 = 'I' ) ( s1 = 'A' s2 = 'N' )
( s1 = 'O' s2 = 'B' ) ( s1 = 'E' s2 = 'R' )
( s1 = 'F' s2 = 'S' ) ( s1 = 'L' s2 = 'Y' )
( s1 = 'P' s2 = 'C' ) ( s1 = 'Z' s2 = 'M' )
).

WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'A' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'BARK' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'BOOK' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'TREAT' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'COMMON' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'SQUAD' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).
WRITE:/ COND string( WHEN word_maker=>can_make_word( word = 'CONFUSE' letter_blocks = blocks ) = abap_true THEN 'True' ELSE 'False' ).

Output:
True
True
False
True
False
True
True

## Action!

DEFINE COUNT="20"
CHAR ARRAY sideA="BXDCNGRTQFJHVAOEFLPZ"
CHAR ARRAY sideB="OKQPATEGDSWUINBRSYCM"
BYTE ARRAY used(COUNT)

BYTE FUNC ToUpper(BYTE c)
IF c>='a AND c<='z THEN
RETURN (c-'a+'A)
FI
RETURN (c)

BYTE FUNC CanBeUsed(CHAR c)
BYTE i

FOR i=0 TO COUNT-1
DO
IF used(i)=0 AND (sideA(i+1)=c OR sideB(i+1)=c) THEN
used(i)=1
RETURN (1)
FI
OD
RETURN (0)

BYTE FUNC Check(CHAR ARRAY s)
BYTE i
CHAR c

FOR i=0 TO COUNT-1
DO used(i)=0 OD

FOR i=1 TO s(0)
DO
c=ToUpper(s(i))
IF CanBeUsed(c)=0 THEN
RETURN (0)
FI
OD
RETURN (1)

PROC Test(CHAR ARRAY s)
Print(s) Print(": ")
IF Check(s) THEN
ELSE
PrintE("can not be made")
FI
RETURN

PROC Main()
Test("a")
Test("bARk")
Test("book")
Test("TReat")
Test("coMMon")
Test("CoNfUsE")
RETURN
Output:
a: can be made
bARk: can be made
book: can not be made
TReat: can be made
coMMon: can not be made
CoNfUsE: can be made

## Acurity Architect

Using #HASH-OFF

FUNCTION bCAN_MAKE_WORD(zWord: STRING): BOOLEAN
VAR sBlockCount: SHORT
VAR sWordCount: SHORT
VAR sWordLength: SHORT
VAR zLetter: STRING
VAR zBlock: STRING
VAR zBlockList: STRING
VAR zUsedBlocks: STRING
VAR zWord: STRING
//
SET zWord = UPPER(zWord)
SET zBlockList = "BO,XK,DQ,CP,NA,GT,RE,TG,QD,FS,JW,HU,VI,AN,OB,ER,FS,LY,PC,ZM"
SET sWordLength = LENGTH(zWord)
//
DO sWordCount = 1 TO sWordLength
DO sBlockCount = 1 TO OCCURS(zBlockList, ",")
SET zLetter = SUBSTR(zWord, sWordCount, 1)
SET zBlock = GET_TOKEN(zBlockList, ",", sBlockCount)
IF INDEX(zBlock, zLetter, 1) > 0 AND INDEX(zUsedBlocks, zBlock + STR(sBlockCount), 1) = 0
SET zUsedBlocks = zUsedBlocks + zBlock + STR(sBlockCount) + ","
BREAK
ENDIF
ENDDO
ENDDO
RETURN OCCURS(zUsedBlocks, ",") = sWordLength
ENDFUNCTION

Output:
bCAN_MAKE_WORD("A") returns TRUE
bCAN_MAKE_WORD("BARK") returns TRUE
bCAN_MAKE_WORD("BOOK") returns FALSE
bCAN_MAKE_WORD("TREAT") returns TRUE
bCAN_MAKE_WORD("COMMON") returns FALSE
bCAN_MAKE_WORD("CONFUSE") returns TRUE

Build with gnatchop abc.ada; gnatmake abc_problem

package Abc is
type Block_Faces is array(1..2) of Character;
type Block_List is array(positive range <>) of Block_Faces;
function Can_Make_Word(W: String; Blocks: Block_List) return Boolean;
end Abc;

package body Abc is

function Can_Make_Word(W: String; Blocks: Block_List) return Boolean is
Used : array(Blocks'Range) of Boolean := (Others => False);
subtype wIndex is Integer range W'First..W'Last;
wPos : wIndex;
begin
if W'Length = 0 then
return True;
end if;
wPos := W'First;
while True loop
declare
C : Character := To_Upper(W(wPos));
X : constant wIndex := wPos;
begin
for I in Blocks'Range loop
if (not Used(I)) then
if C = To_Upper(Blocks(I)(1)) or C = To_Upper(Blocks(I)(2)) then
Used(I) := True;
if wPos = W'Last then
return True;
end if;
wPos := wIndex'Succ(wPos);
exit;
end if;
end if;
end loop;
if X = wPos then
return False;
end if;
end;
end loop;
return False;
end Can_Make_Word;

end Abc;

procedure Abc_Problem is
Blocks : Block_List := (
('B','O'), ('X','K'), ('D','Q'), ('C','P')
, ('N','A'), ('G','T'), ('R','E'), ('T','G')
, ('Q','D'), ('F','S'), ('J','W'), ('H','U')
, ('V','I'), ('A','N'), ('O','B'), ('E','R')
, ('F','S'), ('L','Y'), ('P','C'), ('Z','M')
);
function "+" (S : String) return Unbounded_String renames To_Unbounded_String;
words : array(positive range <>) of Unbounded_String := (
+"A"
, +"BARK"
, +"BOOK"
, +"TREAT"
, +"COMMON"
, +"CONFUSE"
-- Border cases:
-- , +"CONFUSE2"
-- , +""
);
begin
for I in words'Range loop
Put_Line ( To_String(words(I)) & ": " & Boolean'Image(Can_Make_Word(To_String(words(I)),Blocks)) );
end loop;
end Abc_Problem;

Output:
A: TRUE
BARK: TRUE
BOOK: FALSE
TREAT: TRUE
COMMON: FALSE
CONFUSE: TRUE

## ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.win32
# determine whether we can spell words with a set of blocks                  #

# construct the list of blocks #
[][]STRING blocks = ( ( "B", "O" ), ( "X", "K" ), ( "D", "Q" ), ( "C", "P" )
, ( "N", "A" ), ( "G", "T" ), ( "R", "E" ), ( "T", "G" )
, ( "Q", "D" ), ( "F", "S" ), ( "J", "W" ), ( "H", "U" )
, ( "V", "I" ), ( "A", "N" ), ( "O", "B" ), ( "E", "R" )
, ( "F", "S" ), ( "L", "Y" ), ( "P", "C" ), ( "Z", "M" )
);

# Returns TRUE if we can spell the word using the blocks, FALSE otherwise #
# Returns TRUE for an empty string #
PROC can spell = ( STRING word, [][]STRING blocks )BOOL:
BEGIN

# construct a set of flags to indicate whether the blocks are used #
# or not #
[ 1 LWB blocks : 1 UPB blocks ]BOOL used;
FOR block pos FROM LWB used TO UPB used
DO
used[ block pos ] := FALSE
OD;

# initialliy assume we can spell the word #
BOOL result := TRUE;

# check we can spell the word with the set of blocks #
FOR word pos FROM LWB word TO UPB word WHILE result
DO
CHAR c = IF is lower( word[ word pos ] )
THEN to upper( word[ word pos ] )
ELSE word[ word pos ]
FI;

# look through the unused blocks for the current letter #
BOOL found := FALSE;
FOR block pos FROM 1 LWB blocks TO 1 UPB blocks
DO
IF ( c = blocks[ block pos ][ 1 ][ 1 ]
OR c = blocks[ block pos ][ 2 ][ 1 ]
)
AND NOT used[ block pos ]
THEN
# found an unused block with the required letter #
found := TRUE;
used[ block pos ] := TRUE
FI
OD;

result := found

OD;

result
END; # can spell #

main: (

# test the can spell procedure #
PROC test can spell = ( STRING word, [][]STRING blocks )VOID:
write( ( ( "can spell: """
+ word
+ """ -> "
+ IF can spell( word, blocks ) THEN "yes" ELSE "no" FI
)
, newline
)
);

test can spell( "A", blocks );
test can spell( "BaRK", blocks );
test can spell( "BOOK", blocks );
test can spell( "TREAT", blocks );
test can spell( "COMMON", blocks );
test can spell( "SQUAD", blocks );
test can spell( "CONFUSE", blocks )

)

Output:

can spell: "A" -> yes
can spell: "BaRK" -> yes
can spell: "BOOK" -> no
can spell: "TREAT" -> yes
can spell: "COMMON" -> no
can spell: "SQUAD" -> yes
can spell: "CONFUSE" -> yes

## ALGOL W

% determine whether we can spell words with a set of blocks                  %
begin
% Returns true if we can spell the word using the blocks,  %
% false otherwise  %
% As strings are fixed length in Algol W, the length of the string is  %
% passed as a separate parameter  %
logical procedure canSpell ( string(20) value word
; integer value wordLength
) ;
begin

% convert a character to upper-case  %
% assumes the letters are contiguous in the character set  %
% as in ASCII and Unicode - not correct for EBCDIC  %
string(1) procedure toUpper( string(1) value c ) ;
if c < "a" or c > "z" then c
else code( ( decode( c ) - decode( "a" ) )
+ decode( "A" )
) ;

logical spellable;
integer wordPos, blockPos;
string(20) letters1, letters2;

% make local copies the faces so we can remove the used blocks  %
letters1 := face1;
letters2 := face2;

% check we can spell the word with the set of blocks  %
spellable := true;
wordPos  := 0;
while wordPos < wordLength and spellable do begin
string(1) letter;
letter  := toUpper( word( wordPos // 1 ) );
if letter not = " " then begin
spellable := false;
blockPos  := 0;
while blockPos < 20 and not spellable do begin
if letter = letters1( blockPos // 1 )
or letter = letters2( blockPos // 1 )
then begin
% found the letter - remove the used block from the  %
% remaining blocks  %
letters1( blockPos // 1 ) := " ";
letters2( blockPos // 1 ) := " ";
spellable := true
end;
blockPos := blockPos + 1
end
end;
wordPos := wordPos + 1;
end;

spellable
end canSpell ;

% the letters available on the faces of the blocks  %
string(20) face1, face2;
face1 := "BXDCNGRTQFJHVAOEFLPZ";
face2 := "OKQPATEGDSWUINBRSYCM";

begin
% test the can spell procedure  %
procedure testCanSpell ( string(20) value word
; integer value wordLength
) ;
write( if canSpell( word, wordLength ) then "can " else "cannot"
, " spell """
, word
, """"
);

testCanSpell( "a", 1 );
testCanSpell( "bark", 4 );
testCanSpell( "BOOK", 4 );
testCanSpell( "treat", 5 );
testCanSpell( "commoN", 6 );
testCanSpell( "Squad", 5 );
testCanSpell( "confuse", 7 )
end
end.
Output:
can    spell "a                   "
can    spell "bark                "
cannot spell "BOOK                "
can    spell "treat               "
cannot spell "commoN              "
can    spell "Squad               "
can    spell "confuse             "

## Apex

static Boolean canMakeWord(List<String> src_blocks, String word) {
if (String.isEmpty(word)) {
return true;
}

List<String> blocks = new List<String>();
for (String block : src_blocks) {
}

for (Integer i = 0; i < word.length(); i++) {
Integer blockIndex = -1;
String c = word.mid(i, 1).toUpperCase();

for (Integer j = 0; j < blocks.size(); j++) {
if (blocks.get(j).contains(c)) {
blockIndex = j;
break;
}
}

if (blockIndex == -1) {
return false;
} else {
blocks.remove(blockIndex);
}
}

return true;
}

List<String> blocks = new List<String>{
'BO', 'XK', 'DQ', 'CP', 'NA',
'GT', 'RE', 'TG', 'QD', 'FS',
'JW', 'HU', 'VI', 'AN', 'OB',
'ER', 'FS', 'LY', 'PC', 'ZM'
};
System.debug('"": ' + canMakeWord(blocks, ''));
System.debug('"A": ' + canMakeWord(blocks, 'A'));
System.debug('"BARK": ' + canMakeWord(blocks, 'BARK'));
System.debug('"book": ' + canMakeWord(blocks, 'book'));
System.debug('"treat": ' + canMakeWord(blocks, 'treat'));
System.debug('"COMMON": ' + canMakeWord(blocks, 'COMMON'));
System.debug('"CONFUSE": ' + canMakeWord(blocks, 'CONFUSE'));
Output:
"": true
"A": true
"BARK": true
"book": false
"treat": true
"COMMON": false
"CONFUSE": true

## APL

Works with: Dyalog APL version 16.0
abc←{{0=⍴⍵:1 ⋄ 0=⍴h←⊃⍵:0 ⋄ ∇(t←1↓⍵)~¨⊃h:1 ⋄ ∇(⊂1↓h),t}⍸¨↓⍵∘.∊⍺}
Output:
)COPY dfns ucase
b W←(≠∘' '⊆⊢)∘ucase¨'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM' 'A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE'
b∘abc¨W
1 1 0 1 0 1 1

## AppleScript

### Imperative

set blocks to {"bo", "xk", "dq", "cp", "na", "gt", "re", "tg", "qd", "fs", ¬
"jw", "hu", "vi", "an", "ob", "er", "fs", "ly", "pc", "zm"}

canMakeWordWithBlocks("a", blocks)
canMakeWordWithBlocks("bark", blocks)
canMakeWordWithBlocks("book", blocks)
canMakeWordWithBlocks("treat", blocks)
canMakeWordWithBlocks("common", blocks)
canMakeWordWithBlocks("confuse", blocks)

on canMakeWordWithBlocks(theString, constBlocks)
copy constBlocks to theBlocks
if theString = "" then return true
set i to 1
repeat
if i > (count theBlocks) then exit repeat
if character 1 of theString is in item i of theBlocks then
set item i of theBlocks to missing value
set theBlocks to strings of theBlocks
if canMakeWordWithBlocks(rest of characters of theString as string, theBlocks) then
return true
end if
end if
set i to i + 1
end repeat
return false
end canMakeWordWithBlocks

### Functional

use AppleScript version "2.4"
use framework "Foundation"

----------------------- ABC Problem -----------------------

-- spellWith :: [String] -> [Char] -> [[String]]
on spellWith(blocks, cs)
if 0 < length of cs then
set x to item 1 of cs
script go
on |λ|(b)
if b contains x then
map(my cons(b), ¬
spellWith(|delete|(b, blocks), rest of cs))
else
{}
end if
end |λ|
end script
concatMap(go, blocks)
else
{{}}
end if
end spellWith

-------------------------- TEST ---------------------------
on run
set blocks to ¬
words of "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"

script test
on |λ|(w)
justifyRight(9, space, quoted("'", w)) & " -> " & ¬
({} ≠ spellWith(blocks, characters of toUpper(w)))
end |λ|
end script

unlines(map(test, ¬
["", "A", "BARK", "BoOK", "TrEAT", "COmMoN", "SQUAD", "conFUsE"]))
end run

-------------------- GENERIC FUNCTIONS --------------------

-- Just :: a -> Maybe a
on Just(x)
-- Constructor for an inhabited Maybe (option type) value.
-- Wrapper containing the result of a computation.
{type:"Maybe", Nothing:false, Just:x}
end Just

-- Nothing :: Maybe a
on Nothing()
-- Constructor for an empty Maybe (option type) value.
-- Empty wrapper returned where a computation is not possible.
{type:"Maybe", Nothing:true}
end Nothing

-- elemIndex :: Eq a => a -> [a] -> Maybe Int
on elemIndex(x, xs)
set lng to length of xs
repeat with i from 1 to lng
if x = (item i of xs) then return Just(i)
end repeat
return Nothing()
end elemIndex

-- concatMap :: (a -> [b]) -> [a] -> [b]
on concatMap(f, xs)
set lng to length of xs
set acc to {}
tell mReturn(f)
repeat with i from 1 to lng
set acc to acc & (|λ|(item i of xs, i, xs))
end repeat
end tell
return acc
end concatMap

-- cons :: a -> [a] -> [a]
on cons(x)
script
on |λ|(xs)
{x} & xs
end |λ|
end script
end cons

-- delete :: Eq a => a -> [a] -> [a]
on |delete|(x, xs)
set mbIndex to elemIndex(x, xs)
set lng to length of xs

if Nothing of mbIndex then
xs
else
if 1 < lng then
set i to Just of mbIndex
if 1 = i then
items 2 thru -1 of xs
else if lng = i then
items 1 thru -2 of xs
else
tell xs to items 1 thru (i - 1) & items (i + 1) thru -1
end if
else
{}
end if
end if
end |delete|

-- justifyRight :: Int -> Char -> String -> String
on justifyRight(n, cFiller, strText)
if n > length of strText then
text -n thru -1 of ((replicate(n, cFiller) as text) & strText)
else
strText
end if
end justifyRight

-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn

-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
-- The list obtained by applying f
-- to each element of xs.
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map

-- quoted :: Char -> String -> String
on quoted(c, s)
-- string flanked on both sides
-- by a specified quote character.
c & s & c
end quoted

-- replicate :: Int -> String -> String
on replicate(n, s)
set out to ""
if n < 1 then return out
set dbl to s

repeat while (n > 1)
if (n mod 2) > 0 then set out to out & dbl
set n to (n div 2)
set dbl to (dbl & dbl)
end repeat
return out & dbl
end replicate

-- toUpper :: String -> String
on toUpper(str)
set ca to current application
((ca's NSString's stringWithString:(str))'s ¬
uppercaseStringWithLocale:(ca's NSLocale's currentLocale())) as text
end toUpper

-- unlines :: [String] -> String
on unlines(xs)
-- A single string formed by the intercalation
-- of a list of strings with the newline character.
set {dlm, my text item delimiters} to ¬
{my text item delimiters, linefeed}
set s to xs as text
set my text item delimiters to dlm
s
end unlines
Output:
'' -> true
'A' -> true
'BARK' -> true
'BoOK' -> false
'TrEAT' -> true
'COmMoN' -> false
'conFUsE' -> true

## ARM Assembly

Works with: as version Raspberry Pi

/* ARM assembly Raspberry PI */
/* program problemABC.s */

/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */
/************************************/
/* Constantes */
/************************************/
.include "../constantes.inc"
.equ TRUE, 1
.equ FALSE, 0

/*********************************/
/* Initialized data */
/*********************************/
.data
szMessTitre1: .asciz "Can_make_word: @ \n"
szMessTrue: .asciz "True.\n"
szMessFalse: .asciz "False.\n"
szCarriageReturn: .asciz "\n"

szTablBloc: .asciz "BO"
.asciz "XK"
.asciz "DQ"
.asciz "CP"
.asciz "NA"
.asciz "GT"
.asciz "RE"
.asciz "TG"
.asciz "QD"
.asciz "FS"
.asciz "JW"
.asciz "HU"
.asciz "VI"
.asciz "AN"
.asciz "OB"
.asciz "ER"
.asciz "FS"
.asciz "LY"
.asciz "PC"
.asciz "ZM"
.equ NBBLOC, (. - szTablBloc) / 3

szWord1: .asciz "A"
szWord2: .asciz "BARK"
szWord3: .asciz "BOOK"
szWord4: .asciz "TREAT"
szWord5: .asciz "COMMON"
szWord7: .asciz "CONFUSE"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
.align 4
itabTopBloc: .skip 4 * NBBLOC
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: @ entry of program
bl traitBlock @ control word

bl traitBlock @ control word

bl traitBlock @ control word

bl traitBlock @ control word

bl traitBlock @ control word

bl traitBlock @ control word

bl traitBlock @ control word

100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc #0 @ perform the system call

/******************************************************************/
/* traitement */
/******************************************************************/
/* r0 contains word */
traitBlock:
push {r1,lr} @ save registers
mov r1,r0
ldr r0,iAdrszMessTitre1 @ insertion word in message
bl strInsertAtCharInc
bl affichageMess @ display title message
mov r0,r1
bl controlBlock @ control
cmp r0,#TRUE @ ok ?
bne 1f
ldr r0,iAdrszMessTrue @ yes
bl affichageMess
b 100f
1: @ no
bl affichageMess
100:
pop {r1,lr}
bx lr @ return
/******************************************************************/
/* control if letters are in block */
/******************************************************************/
/* r0 contains word */
controlBlock:
push {r1-r9,lr} @ save registers
mov r5,r0 @ save word address
mov r2,#0
mov r3,#0
1: @ init table top block used
str r3,[r4,r2,lsl #2]
cmp r2,#NBBLOC
blt 1b
mov r2,#0
2: @ loop to load letters
ldrb r3,[r5,r2]
cmp r3,#0
beq 10f @ end
and r3,r3,#0xDF @ transform in capital letter
mov r8,#0
3: @ begin loop control block
ldr r7,[r4,r8,lsl #2] @ block already used ?
cmp r7,#0
bne 5f @ yes
add r9,r8,r8,lsl #1 @ no -> index * 3
ldrb r7,[r6,r9] @ first block letter
cmp r3,r7 @ equal ?
beq 4f
ldrb r7,[r6,r9] @ second block letter
cmp r3,r7 @ equal ?
beq 4f
b 5f
4:
mov r7,#1 @ top block
str r7,[r4,r8,lsl #2] @ block used
b 2b @ next letter
5:
cmp r8,#NBBLOC
blt 3b
mov r0,#FALSE @ no letter find on block -> false
b 100f
10: @ all letters are ok
mov r0,#TRUE
100:
pop {r1-r9,lr}
bx lr @ return
/***************************************************/
/* ROUTINES INCLUDE */
/***************************************************/
.include "../affichage.inc"

Can_make_word: A
True.
Can_make_word: BARK
True.
Can_make_word: BOOK
False.
Can_make_word: TREAT
True.
Can_make_word: COMMON
False.
True.
Can_make_word: CONFUSE
True.

## Arturo

blocks: map [
[B O] [X K] [D Q] [C P] [N A] [G T] [R E]
[T G] [Q D] [F S] [J W] [H U] [V I] [A N]
[O B] [E R] [F S] [L Y] [P C] [Z M]
] => [ join map & => [to :string]]

charInBlock: function [ch,bl][
loop.with:'i bl 'b ->
if contains? b upper ch [
return i
]
return ø
]

canMakeWord?: function [wrd][
ref: new blocks
loop split wrd 'chr [
cib: charInBlock chr ref
if? cib = ø [ return false ]
else [ ref: remove ref .index cib ]
]
return true
]

loop ["A" "BaRk" "bOoK" "tReAt" "CoMmOn" "SqUaD" "cONfUsE"] 'wrd
-> print [wrd "=>" canMakeWord? wrd]
Output:
A => true
BaRk => true
bOoK => false
tReAt => true
CoMmOn => false
cONfUsE => true

## Astro

fun abc(s, ls):
if ls.isempty:
return true
for i in indices(list) where s[end] in list[i]:
return abc(s[:end-1], remove!(copy(list), at: i))
false

let test = ["A", "BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"]
let ls = ["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS", "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]

for s in test:
print "(\$|>8|{s} \${abc(s, list)})"

## AutoHotkey

Function

isWordPossible(blocks, word){
o := {}
loop, parse, blocks, `n, `r
o.Insert(A_LoopField)
loop, parse, word
if !(r := isWordPossible_contains(o, A_LoopField, word))
return 0
return 1
}
isWordPossible_contains(byref o, letter, word){
loop 2 {
for k,v in o
if Instr(v,letter)
{
StringReplace, op, v,% letter
if RegExMatch(op, "[" word "]")
sap := k
else added := 1 , sap := k
return "1" o.remove(sap)
}
}
}

Test Input (as per question)

blocks := "
(
BO
XK
DQ
CP
NA
GT
RE
TG
QD
FS
JW
HU
VI
AN
OB
ER
FS
LY
PC
ZM
)"

wordlist := "
(
A
BARK
BOOK
TREAT
COMMON
CONFUSE
)"

loop, parse, wordlist, `n
out .= A_LoopField " - " isWordPossible(blocks, A_LoopField) "`n"
msgbox % out
Output:
A - 1
BARK - 1
BOOK - 0
TREAT - 1
COMMON - 0
CONFUSE - 1

## AWK

Here are 2 slightly different versions:

#!/usr/bin/awk -f
# tested with mawk 1.3.3 on Raspberry Pi 3
#        also GNU awk 3.1.5, busybox 1.21.1 and 1.27.1 on AMD Sempron 2800+
#
function setblocks() {
# key to the algorithm is the representation of a block
# each block is represented by 4 characters in the string "blocks"
# for example, the "BO" block becomes "-BO-"
#
blocks="-BO--XK--DQ--CP--NA--GT--RE--TG--QD--FS--JW--HU--VI--AN--OB--ER--FS--LY--PC--ZM-"
true=1
false=0
}
function found(letter){
#
# the function "found" scans for the letter on the top of a block
# using the pattern "-B", for example, to find a "B",
# returning "true" (or 1) if found
# if not found on the top, look on the bottoms using the pattern "B-"
# again returning "true" if found
# if the letter is found on either top or bottom, the 4 character block is set to "----"
# so that block is unavailable
# finally, if no available copy of letter is found,
# the function returns "false" (0)
position= index(blocks,"-" letter)
if (position > 0)
{
blocks = substr(blocks,1,position-1) "----" substr(blocks,position+4)
return true
}
position = index(blocks,letter "-")
if (position > 0)
{blocks = substr(blocks,1,position-3) "----" substr(blocks,position+2)
return true
}
return false
}
# awk's BEGIN statement allows for initialization before processing input;
# in this case, initializing the string "blocks"
#
BEGIN{
setblocks()
}
# in awk, the input record is contained in the string variable "\$0"
# the main process checks each letter in turn to see if it is on a usable block,
# summing the values returned by "found"
# if the sum equals the number of input characters the word can be spelled with the blocks
# otherwise it is not possible
#
{
nchars=length(\$0)
possible=false
for (i=1;i<=nchars;i++){
possible=possible + found(substr(\$0,i,1))
}
if (possible==nchars) print \$0 " is possible"
else print \$0 " is not possible"
setblocks()
}

and -----------------
#!/usr/bin/awk -f
# tested with mawk 1.3.3 on Raspberry Pi 3
#        also GNU awk 3.1.5, busybox 1.21.1 and 1.27.1 on AMD Sempron 2800+
#
function setblocks() {
#
#  key to the algorithm is the representation of the blocks
# each block is represented by 1 character in the string "tops"
# and by 1 character in the string "bottoms"
#
tops="BXDCNGRTQFJHVAOEFLPZ"
bottoms="OKQPATEGDSWUINBRSYCM"
true=1
false=0
}
function found(letter){
#
# the function "found" scans first the string "tops" for a letter and
# then the string "bottoms" if the letter is not in "tops"
# if the letter is found, it marks "tops" and "bottoms" to show
# the block is unavailable by changing the letters on the block to "-"
# and returns "true" (1); if the letter is not found
# the function returns "false" (0)
#
position= index(tops,letter)
if (position > 0)
{
tops = substr(tops,1,position-1) "-" substr(tops,position+1)
bottoms = substr(bottoms,1,position-1) "-" substr(bottoms,position+1)
return true
}
position = index(bottoms,letter)
if (position > 0)
{bottoms = substr(bottoms,1,position-1) "-" substr(bottoms,position+1)
tops = substr(tops,1,position-1) "-" substr(tops,position+1)
return true
}
return false
}
# awk's BEGIN statement allows for initialization before processing input;
# in this case, initializing the string "blocks"
#
BEGIN{
setblocks()
}
# in awk, the input record is contained in the string variable "\$0"
# the main process checks each letter in turn to see if it is on a usable block,
# summing the values returned by "found"
# if the sum equals the number of input characters the word can be spelled with the blocks
# otherwise it is not possible
#
{
nchars=length(\$0)
possible=false
for (i=1;i<=nchars;i++){
possible=possible + found(substr(\$0,i,1))
}
if (possible==nchars) print \$0 " is possible"
else print \$0 " is not possible"
setblocks()
}
Output:
[email protected]:~/Documents/rosettacode \$ ./abcProblem.awk
A
A is possible
BARK
BARK is possible
BOOK
BOOK is not possible
TREAT
TREAT is possible
COMMON
COMMON is not possible
CONFUSE
CONFUSE is possible
^C
[email protected]:~/Documents/rosettacode \$

## BaCon

CONST info\$ = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"

DATA "A", "BARK", "BOOK", "TREAT", "Common", "Squad", "Confuse"

WHILE TRUE

IF NOT(LEN(word\$)) THEN BREAK

block\$ = info\$

count = AMOUNT(block\$)

FOR y = 1 TO LEN(word\$)
FOR x = 1 TO AMOUNT(block\$)
IF TALLY(TOKEN\$(block\$, x), MID\$(UCASE\$(word\$), y, 1)) THEN
block\$ = DEL\$(block\$, x)
BREAK
END IF
NEXT
NEXT

PRINT word\$, IIF\$(LEN(word\$) = count-AMOUNT(block\$), "True", "False") FORMAT "%-10s: %s\n"
WEND
Output:
A         : True
BARK      : True
BOOK      : False
TREAT     : True
Common    : False
Confuse   : True

## BASIC

Works with:VB-DOS, QB64, QBasic, QuickBASIC

' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '
' ABC_Problem '
' '
' Developed by A. David Garza Marín in VB-DOS for '
' RosettaCode. November 29, 2016. '
' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' '

' Comment the following line to run it in QB or QBasic
OPTION EXPLICIT ' Modify to OPTION _EXPLICIT for QB64

' SUBs and FUNCTIONs
DECLARE SUB doCleanBlocks ()
DECLARE FUNCTION ICanMakeTheWord (WhichWord AS STRING) AS INTEGER
DECLARE SUB doReadBlocks ()

' rBlock Data Type
TYPE regBlock
Block AS STRING * 2
Used AS INTEGER
END TYPE

' Initialize
CONST False = 0, True = NOT False, HMBlocks = 20
DATA "BO", "XK", "DQ", "CP", "NA", "GT","RE", "TG"
DATA "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER"
DATA "FS", "LY", "PC","ZM"

DIM rBlock(1 TO HMBlocks) AS regBlock
DIM i AS INTEGER, aWord AS STRING, YorN AS STRING

doReadBlocks ' Read the data in the blocks

'-------------- Main program cycle ------------------
CLS
PRINT "This program has the following blocks: ";
FOR i = 1 TO HMBlocks
PRINT rBlock(i).Block; "|";
NEXT i
PRINT : PRINT
PRINT "Please, write a word or a short sentence to see if the available"
PRINT "blocks can make it. If so, I will tell you."
DO
doCleanBlocks ' Clean all blocks
PRINT
INPUT "Which is the word"; aWord
aWord = LTRIM\$(RTRIM\$(aWord))

IF aWord <> "" THEN
IF ICanMakeTheWord(aWord) THEN
PRINT "Yes, i can make it."
ELSE
PRINT "No, I can't make it."
END IF
ELSE
PRINT "At least, you need to type a letter."
END IF

PRINT
PRINT "Do you want to try again (Y/N) ";
DO
YorN = INPUT\$(1)
YorN = UCASE\$(YorN)
LOOP UNTIL YorN = "Y" OR YorN = "N"
PRINT YorN

LOOP UNTIL YorN = "N"
' -------------- End of Main program ----------------
END

SUB doCleanBlocks ()
' Var
SHARED rBlock() AS regBlock
DIM i AS INTEGER

' Will clean the Used status of all blocks
FOR i = 1 TO HMBlocks
rBlock(i).Used = False
NEXT i

END SUB

' Var
SHARED rBlock() AS regBlock
DIM i AS INTEGER

' Will read the block values from DATA
FOR i = 1 TO HMBlocks
NEXT i
END SUB

FUNCTION ICanMakeTheWord (WhichWord AS STRING) AS INTEGER ' Comment AS INTEGER to run in QBasic, QB64 and QuickBASIC
' Var
SHARED rBlock() AS regBlock
DIM i AS INTEGER, l AS INTEGER, j AS INTEGER, iYesICan AS INTEGER
DIM c AS STRING, sUWord AS STRING

' Will evaluate if can make the word
sUWord = UCASE\$(WhichWord)
l = LEN(sUWord)
i = 0

DO
i = i + 1
iYesICan = False
c = MID\$(sUWord, i, 1)
j = 0
DO
j = j + 1
IF NOT rBlock(j).Used THEN
iYesICan = (INSTR(rBlock(j).Block, c) > 0)
rBlock(j).Used = iYesICan
END IF
LOOP UNTIL j >= HMBlocks OR iYesICan

LOOP UNTIL i >= l OR NOT iYesICan

' The result will depend on the last value of
' iYesICan variable. If the last value is True
' is because the function found even the last
' letter analyzed.
ICanMakeTheWord = iYesICan

END FUNCTION

### Commodore BASIC

Translation of: Sinclair ZX-81 BASIC
10 W\$ = "A" : GOSUB 100
20 W\$ = "BARK" : GOSUB 100
30 W\$ = "BOOK" : GOSUB 100
40 W\$ = "TREAT" : GOSUB 100
50 W\$ = "COMMON" : GOSUB 100
60 W\$ = "SQUAD" : GOSUB 100
70 W\$ = "CONFUSE" : GOSUB 100
80 END
90 REM ********************************
100 B\$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
110 FOR I=1 TO LEN(W\$)
120 : BL = LEN(B\$)
130 : FOR J=1 TO BL STEP 2
140 : C\$=MID\$(B\$,J,1): D\$=MID\$(B\$,J+1,1)
150 : X\$=MID\$(W\$,I,1)
160 : IF C\$<>X\$ AND D\$<>X\$ THEN GOTO 190
170 : B\$ = LEFT\$(B\$,J-1)+RIGHT\$(B\$,BL-J-1)
180 : GOTO 210
190 : NEXT J
200 : IF J>BL-1 THEN GOTO 240
210 NEXT I
220 PRINT W\$" -> YES"
230 RETURN
240 PRINT W\$" -> NO"
250 RETURN
Output:
A -> YES
BARK -> YES
BOOK -> NO
TREAT -> YES
COMMON -> NO
CONFUSE -> YES

The above greedy algorithm works on the sample data, but fails on other data - for example, it will declare that you cannot spell the word ABBA using the blocks (AB),(AB),(AC),(AC), because it will use the two AB blocks for the first two letters "AB", leaving none for the second "B". This recursive solution is more thorough about confirming negatives and handles that case correctly:

100 REM RECURSIVE SOLUTION
110 MS=100:REM MAX STACK DEPTH
120 DIM BL\$(MS):REM BLOCKS LEFT
130 DIM W\$(MS):REM REMAINING LETTERS
140 DIM I(MS):REM LOOP CONTROL VARIABLE
150 DIM RV(MS):REM RETURN VALUE
160 SP=-1:REM STACK POINTER
180 PRINT "USING BLOCKS: "
190 FOR I=1 TO LEN(BL\$) STEP 2
200 : PRINT"("MID\$(BL\$,I,2)")";
210 NEXT I
220 PRINT CHR\$(13)
240 IF W\$="" THEN 320
250 PRINT W\$;"->";
260 SP=SP+1:BL\$(SP)=BL\$:W\$(SP)=W\$
270 GOSUB 350
280 IF RV(SP) THEN PRINT "YES": GOTO 300
290 PRINT "NO"
300 SP=SP-1
310 GOTO 230
330 IF BL\$ THEN PRINT:GOTO 180
340 END
350 IF LEN(W\$(SP))=0 THEN RV(SP)=-1:RETURN
360 I(SP)=1
370 IF I(SP)>=LEN(BL\$(SP)) THEN RV(SP)=0:RETURN
380 IF MID\$(BL\$(SP),I(SP),1) = LEFT\$(W\$(SP),1) THEN 410
390 IF MID\$(BL\$(SP),I(SP)+1,1) = LEFT\$(W\$(SP),1) THEN 410
400 GOTO 450
410 W\$(SP+1)=MID\$(W\$(SP),2)
420 BL\$(SP+1)=LEFT\$(BL\$(SP),I(SP)-1)+MID\$(BL\$(SP),I(SP)+2)
430 SP=SP+1:GOSUB 350:SP=SP-1
440 IF RV(SP+1) THEN RV(SP)=-1:RETURN
450 I(SP)=I(SP)+2:GOTO 370
460 DATA BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM
470 DATA A, BORK, BOOK, TREAT, COMMON, SQUAD, CONFUSE, ""
480 DATA ABABACAC,ABBA,""
490 DATA ""
Output:
USING BLOCKS:
(BO)(XK)(DQ)(CP)(NA)(GT)(RE)(TG)(QD)(FS)
(JW)(HU)(VI)(AN)(OB)(ER)(FS)(LY)(PC)(ZM)

A->YES
BORK->YES
BOOK->NO
TREAT->YES
COMMON->NO
CONFUSE->YES

USING BLOCKS:
(AB)(AB)(AC)(AC)

ABBA->YES

### Sinclair ZX81 BASIC

Works with 1k of RAM. A nice unstructured algorithm. Unfortunately the requirement that it be case-insensitive is moot, because the ZX81 does not support lower-case letters.

10 LET B\$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
20 INPUT W\$
30 FOR I=1 TO LEN W\$
40 FOR J=1 TO LEN B\$ STEP 2
50 IF B\$(J)<>W\$(I) AND B\$(J+1)<>W\$(I) THEN GOTO 100
60 LET B\$=B\$( TO J-1)+B\$(J+2 TO )
70 NEXT I
80 PRINT "YES"
90 STOP
100 NEXT J
110 PRINT "NO"
Input:
A
Output:
YES
Input:
BARK
Output:
YES
Input:
BOOK
Output:
NO
Input:
TREAT
Output:
YES
Input:
COMMON
Output:
NO
Input:
Output:
YES
Input:
CONFUSE
Output:
YES

## Batch File

@echo off
::abc.bat
::
::Batch file to evaluate if a given string can be represented with a set of
::20 2-faced blocks.
::

::Check if a string was provided

if "%1"=="" goto ERROR

::Define blocks. Separate blocks by ':', and terminat with '::'

set "FACES=BO:XK:DQ:CP:NA:GT:RE:TG:QD:FS:JW:HU:VI:AN:OB:ER:FS:LY:PC:ZM::"
set INPUT=%1
set "COUNTER=0"

::The main loop steps through the input string, checking if an available

::block exists for each character
:LOOP_MAIN

::Get character, increase counter, and test if there are still characters

call set "char=%%INPUT:~%COUNTER%,1%%"
set /a "COUNTER+=1"
if "%CHAR%"=="" goto LOOP_MAIN_END

set "OFFSET=0"
:LOOP_2

::Read in two characters (one block)

call set "BLOCK=%%FACES%:~%OFFSET%,2%%"

::Test if the all blocks were checked. If so, no match was found

if "%BLOCK%"==":" goto FAIL

::Test if current input string character is in the current block

if /i "%BLOCK:~0,1%"=="%CHAR%" goto FOUND
if /i "%BLOCK:~1,1%"=="%CHAR%" goto FOUND

::Increase offset to point to the next block

set /a "OFFSET+=3"

goto LOOP_2
:LOOP_2_END

::If found, blank out the block used

:FOUND
call set "FACES=%%FACES:%BLOCK%:=  :%%"

goto LOOP_MAIN
:LOOP_MAIN_END

echo %0: It is possible to write the '%INPUT%' with my blocks.
goto END

:FAIL
echo %0: It is NOT possible to write the '%INPUT%' with my blocks.
goto END

:ERROR
echo %0: Please enter a string to evaluate
echo.

:END

## BBC BASIC

BLOCKS\$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
PROCcan_make_word("A")
PROCcan_make_word("BARK")
PROCcan_make_word("BOOK")
PROCcan_make_word("TREAT")
PROCcan_make_word("COMMON")
PROCcan_make_word("Confuse")
END

DEF PROCcan_make_word(word\$)
LOCAL b\$,p%
b\$=BLOCKS\$
PRINT word\$ " -> ";
p%=INSTR(b\$,CHR\$(ASCword\$ AND &DF))
WHILE p%>0 AND word\$>""
MID\$(b\$,p%-1+(p% MOD 2),2)=".."
word\$=MID\$(word\$,2)
p%=INSTR(b\$,CHR\$(ASCword\$ AND &DF))
ENDWHILE
IF word\$>"" PRINT "False" ELSE PRINT "True"
ENDPROC
Output:
A -> True
BARK -> True
BOOK -> False
TREAT -> True
COMMON -> False
Confuse -> True

## BCPL

get "libhdr"

let canMakeWord(word) = valof
\$( let blocks = "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
let avl = vec 40/BYTESPERWORD
for i=0 to 39 do avl%i := blocks%(i+1)
for i=1 to word%0
\$( for j=0 to 39
\$( let ch = word%i
// make letter uppercase
if 'a' <= ch <= 'z' then ch := ch - 32
if ch = avl%j then
\$( // this block is no longer available
avl%j := 0
avl%(j neqv 1) := 0
// but we did find a block
goto next
\$)
\$)
resultis false // no block found
next: loop
\$)
resultis true
\$)

let show(word) be
writef("%S: %S*N", word, canMakeWord(word) -> "yes", "no")

let start() be
\$( show("A")
show("BARK")
show("book")
show("Treat")
show("CoMmOn")
show("CONFUSE")
\$)
Output:
A: yes
BARK: yes
book: no
Treat: yes
CoMmOn: no
CONFUSE: yes

## BQN

ABC ← {
Matches ← ⊑⊸(⊑∘∊¨)˜ /⊣ # blocks matching current letter
Others ← <˘∘⍉∘(»⊸≥∨`)∘(≡⌜)/¨<∘⊣ # blocks without current matches
𝕨(×∘≠∘⊢ ◶ ⟨1˙, # if the word is empty, it can be made
Matches(×∘≠∘⊣ ◶ ⟨0˙, # if no matching blocks, it cannot
∨´(𝕨 Others⊣) 𝕊¨ 1<∘↓⊢ # otherwise, remove block and try remaining letters
⟩)⊢
⟩) (⊢-32×1="a{"⍋⊢)𝕩
}

blocks←⟨"BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
"JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"⟩

> {(<𝕩) ∾ blocks ABC 𝕩}¨ words
Output:
┌─
╵ "A"       1
"bark"    1
"BOOK"    0
"TrEaT"   1
"Common"  0
"Confuse" 1
┘

## Bracmat

(
( can-make-word
= ABC blocks
. (B O)
+ (X K)
+ (D Q)
+ (C P)
+ (N A)
+ (G T)
+ (R E)
+ (T G)
+ (Q D)
+ (F S)
+ (J W)
+ (H U)
+ (V I)
+ (A N)
+ (O B)
+ (E R)
+ (F S)
+ (L Y)
+ (P C)
+ (Z M)
: ?blocks
& ( ABC
= letter blocks A Z
.  !arg:(.?)
|  !arg:(@(?:%?letter ?arg).?blocks)
&  !blocks
:  ?
+ ?*(? !letter ?:?block)
+ (?&ABC\$(!arg.!blocks+-1*!block))
)
& out
\$ ( !arg
( ABC\$(upp\$!arg.!blocks)&yes
| no
)
)
)
& can-make-word'A
& can-make-word'BARK
& can-make-word'BOOK
& can-make-word'TREAT
& can-make-word'COMMON
& can-make-word'CONFUSE
);
Output:
A yes
BARK yes
BOOK no
TREAT yes
COMMON no
CONFUSE yes

## C

Recursive solution. Empty string returns true.

#include <stdio.h>
#include <ctype.h>

int can_make_words(char **b, char *word)
{
int i, ret = 0, c = toupper(*word);

#define SWAP(a, b) if (a != b) { char * tmp = a; a = b; b = tmp; }

if (!c) return 1;
if (!b[0]) return 0;

for (i = 0; b[i] && !ret; i++) {
if (b[i][0] != c && b[i][1] != c) continue;
SWAP(b[i], b[0]);
ret = can_make_words(b + 1, word + 1);
SWAP(b[i], b[0]);
}

return ret;
}

int main(void)
{
char* blocks[] = {
"BO", "XK", "DQ", "CP", "NA",
"GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB",
"ER", "FS", "LY", "PC", "ZM",
0 };

char *words[] = {
"", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse", 0
};

char **w;
for (w = words; *w; w++)
printf("%s\t%d\n", *w, can_make_words(blocks, *w));

return 0;
}
Output:
1
A       1
BARK    1
BOOK    0
TREAT   1
COMMON  0
Confuse 1

## C#

### Regex

This Method uses regular expressions to do the checking. Given that n = length of blocks string and m = length of word string, then CheckWord's time complexity comes out to about m*(n - (m-1)/2).

using System;
using System.IO;
// Needed for the method.
using System.Text.RegularExpressions;
using System.Collections.Generic;

void Main()
{
string blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";
List<string> words = new List<string>() {
"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"
};

foreach(var word in words)
{
Console.WriteLine("{0}: {1}", word, CheckWord(blocks, word));
}
}

bool CheckWord(string blocks, string word)
{
for(int i = 0; i < word.Length; ++i)
{
int length = blocks.Length;
Regex rgx = new Regex("([a-z]"+word[i]+"|"+word[i]+"[a-z])", RegexOptions.IgnoreCase);
blocks = rgx.Replace(blocks, "", 1);
if(blocks.Length == length) return false;
}
return true;
}

Output:
A: True
BARK: True
BOOK: False
TREAT: True
COMMON: False
CONFUSE: True

Unoptimized

using System.Collections.Generic;
using System.Linq;

void Main()
{
List<string> blocks =
new List<string>() { "bo", "xk", "dq", "cp", "na", "gt", "re", "tg", "qd", "fs",
"jw", "hu", "vi", "an", "ob", "er", "fs", "ly", "pc", "zm" };
List<string> words = new List<string>() {
"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"};

var solver = new ABC(blocks);

foreach( var word in words)
{
Console.WriteLine("{0} :{1}", word, solver.CanMake(word));
}
}

class ABC
{
readonly Dictionary<char, List<int>> _blockDict = new Dictionary<char, List<int>>();
bool[] _used;
int _nextBlock;

private void AddBlockChar(char c)
{
if (!_blockDict.ContainsKey(c))
{
_blockDict[c] = new List<int>();
}
}

private void AddBlock(string block)
{
_nextBlock++;
}

public ABC(List<string> blocks)
{
_blocks = blocks;
foreach (var block in blocks)
{
}
}

public bool CanMake(string word)
{
word = word.ToLower();
if (word.Length > _blockDict.Count)
{
return false;
}
_used = new bool[_blocks.Count];
return TryMake(word);
}

public bool TryMake(string word)
{
if (word == string.Empty)
{
return true;
}
var blocks = _blockDict[word[0]].Where(b => !_used[b]);
foreach (var block in blocks)
{
_used[block] = true;
if (TryMake(word.Substring(1)))
{
return true;
}
_used[block] = false;
}
return false;
}
}

Output:
A :True
BARK :True
BOOK :False
TREAT :True
COMMON :False
CONFUSE :True

## C++

Works with: C++11

Build with:

g++-4.7 -Wall -std=c++0x abc.cpp
#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <cctype>

typedef std::pair<char,char> item_t;
typedef std::vector<item_t> list_t;

bool can_make_word(const std::string& w, const list_t& vals) {
std::set<uint32_t> used;
while (used.size() < w.size()) {
const char c = toupper(w[used.size()]);
uint32_t x = used.size();
for (uint32_t i = 0, ii = vals.size(); i < ii; ++i) {
if (used.find(i) == used.end()) {
if (toupper(vals[i].first) == c || toupper(vals[i].second) == c) {
used.insert(i);
break;
}
}
}
if (x == used.size()) break;
}
return used.size() == w.size();
}

int main() {
list_t vals{ {'B','O'}, {'X','K'}, {'D','Q'}, {'C','P'}, {'N','A'}, {'G','T'}, {'R','E'}, {'T','G'}, {'Q','D'}, {'F','S'}, {'J','W'}, {'H','U'}, {'V','I'}, {'A','N'}, {'O','B'}, {'E','R'}, {'F','S'}, {'L','Y'}, {'P','C'}, {'Z','M'} };
for (const std::string& w : words) {
std::cout << w << ": " << std::boolalpha << can_make_word(w,vals) << ".\n";
}
}
Output:
A: true.
BARK: true.
BOOK: false.
TREAT: true.
COMMON: false.
CONFUSE: true.

## Ceylon

Functional programming/recursive solution. No variable values.

module.ceylon

module rosetta.abc "1.0.0" {}

run.ceylon

shared void run() {
printAndCanMakeWord("A", blocks);
//True
printAndCanMakeWord("BARK", blocks);
//True
printAndCanMakeWord("BOOK", blocks);
//False
printAndCanMakeWord("TREAT", blocks);
//True
printAndCanMakeWord("COMMON", blocks);
//False
//True
printAndCanMakeWord("CONFUSE", blocks);
//True
}

Block[] blocks =
[
Block('B','O'),
Block('X','K'),
Block('D','Q'),
Block('C','P'),
Block('N','A'),
Block('G','T'),
Block('R','E'),
Block('T','G'),
Block('Q','D'),
Block('F','S'),
Block('J','W'),
Block('H','U'),
Block('V','I'),
Block('A','N'),
Block('O','B'),
Block('E','R'),
Block('F','S'),
Block('L','Y'),
Block('P','C'),
Block('Z','M')
];

void printAndCanMakeWord(String word, Block[] blocks) {
print("``word``:``canMakeWord(word, blocks)``");
}

class Block(Character firstLetter, Character secondLetter) {
shared Character firstLetterUpper = firstLetter.uppercased;
shared Character secondLetterUpper = secondLetter.uppercased;

shared Boolean containsLetter(Character letter)
=> let (letterUpper = letter.uppercased)
firstLetterUpper == letterUpper || secondLetterUpper == letterUpper;

shared actual String string = "``firstLetterUpper``,``secondLetterUpper``";
}

Boolean canMakeWord(String word, Block[] blocks)
=> canMakeWordRecursive(word.uppercased.sequence(), 0, blocks, word.indexes());

Boolean canMakeWordRecursive(Character[] word,
Integer index,
Block[] remainingBlocks,
Integer[] remainingLetterIndexes)
=> if (exists wordFirst = word.first, // first is the Ceylon attribute for head
exists remainingBlock = remainingBlocks.find((remainingBlock) => remainingBlock.containsLetter(wordFirst)))
then
let (myRemainingLetterIndexes = remainingLetterIndexes.filter((theIndex) => index != theIndex).sequence())
if (myRemainingLetterIndexes.empty)
then true
else canMakeWordRecursive(word.rest,// rest is the Ceylon attribute for tail
index+1, // move through the letter indexes
remainingBlocks.filter((block) => remainingBlock != block).sequence(), // one less block
myRemainingLetterIndexes)
else false;

Output:
A:true
BARK:true
BOOK:false
TREAT:true
COMMON:false
CONFUSE:true

## Clojure

A translation of the Haskell solution.

(def blocks
(-> "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM" (.split " ") vec))

(defn omit
"return bs with (one instance of) b omitted"
[bs b]
(let [[before after] (split-with #(not= b %) bs)]
(concat before (rest after))))

(defn abc
"return lazy sequence of solutions (i.e. block lists)"
[blocks [c & cs]]
(if (some? c)
(for [b blocks :when (some #(= c %) b)
bs (abc (omit blocks b) cs)]
(cons b bs))
[[]]))

(doseq [word ["A" "BARK" "Book" "treat" "COMMON" "SQUAD" "CONFUSE"]]
(->> word .toUpperCase (abc blocks) first (printf "%s: %b\n" word)))
Output:
A: true
BARK: true
Book: false
treat: true
COMMON: false
CONFUSE: true

## CLU

ucase = proc (s: string) returns (string)
rslt: array[char] := array[char]\$predict(1,string\$size(s))
for c: char in string\$chars(s) do
if c>='a' & c<='z' then
c := char\$i2c(char\$c2i(c) - 32)
end
end
return(string\$ac2s(rslt))
end ucase

abc = proc (s: string) returns (bool)
own collection: sequence[string] := sequence[string]\$
["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
"JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]

blocks: array[string] := sequence[string]\$s2a(collection)
for c: char in string\$chars(ucase(s)) do
begin
for i: int in array[string]\$indexes(blocks) do
if string\$indexc(c, blocks[i]) ~= 0 then
blocks[i] := ""
exit found
end
end
return(false)
end
except when found: end
end
return(true)
end abc

start_up = proc ()
po: stream := stream\$primary_output()
words: sequence[string] := sequence[string]\$
["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"]

for word: string in sequence[string]\$elements(words) do
stream\$puts(po, word || ": ")
if abc(word) then stream\$putl(po, "yes")
else stream\$putl(po, "no")
end
end
end start_up
Output:
A: yes
BARK: yes
BOOK: no
TREAT: yes
COMMON: no
CONFUSE: yes

## CoffeeScript

blockList = [ 'BO', 'XK', 'DQ', 'CP', 'NA', 'GT', 'RE', 'TG', 'QD', 'FS', 'JW', 'HU', 'VI', 'AN', 'OB', 'ER', 'FS', 'LY', 'PC', 'ZM' ]

canMakeWord = (word="") ->
# Create a shallow clone of the master blockList
blocks = blockList.slice 0
# Check if blocks contains letter
checkBlocks = (letter) ->
# Loop through every remaining block
for block, idx in blocks
# If letter is in block, blocks.splice will return an array, which will evaluate as true
return blocks.splice idx, 1 if letter.toUpperCase() in block
false
# Return true if there are no falsy values
false not in (checkBlocks letter for letter in word)

# Expect true, true, false, true, false, true, true, true
for word in ["A", "BARK", "BOOK", "TREAT", "COMMON", "squad", "CONFUSE", "STORM"]
console.log word + " -> " + canMakeWord(word)
Output:
A -> true
BARK -> true
BOOK -> false
TREAT -> true
COMMON -> false
CONFUSE -> true
STORM -> true

## Comal

0010 FUNC can'make'word#(word\$) CLOSED
0020 blocks\$:=" BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
0030 FOR i#:=1 TO LEN(word\$) DO
0040 pos#:=UPPER\$(word\$(i#)) IN blocks\$
0050 IF NOT pos# THEN RETURN FALSE
0060 blocks\$(pos#):="";blocks\$(pos# BITXOR 1):=""
0070 ENDFOR i#
0080 RETURN TRUE
0090 ENDFUNC
0100 //
0110 DIM yesno\$(0:1) OF 3
0120 yesno\$(FALSE):="no";yesno\$(TRUE):="yes"
0130 WHILE NOT EOD DO
0150 PRINT w\$,": ",yesno\$(can'make'word#(w\$))
0160 ENDWHILE
0170 END
0180 //
Output:
A: yes
BARK: yes
BOOK: no
treat: yes
common: no
CoNfUsE: yes

## Common Lisp

(defun word-possible-p (word blocks)
(cond
((= (length word) 0) t)
((null blocks) nil)
(t (let*
((c (aref word 0))
(bs (remove-if-not #'(lambda (b)
(find c b :test #'char-equal))
blocks)))
(some #'identity
(loop for b in bs
collect (word-possible-p
(subseq word 1)
(remove b blocks))))))))
Output:
> (defparameter *blocks*
'("BO" "XK" "DQ" "CP" "NA" "GT" "RE" "TG" "QD" "FS"
"JW" "HU" "VI" "AN" "OB" "ER" "FS" "LY" "PC" "ZM"))
> (dolist (w '("" "A" "bArk" "BOOK" "trEAt" "CoMmoN" "squad" "conFUse"))
(format t "~s is possible: ~a~%" w (word-possible-p w *blocks*)))
"" is possible: T
"A" is possible: T
"bArk" is possible: T
"BOOK" is possible: NIL
"trEAt" is possible: T
"CoMmoN" is possible: NIL
"squad" is possible: T
"conFUse" is possible: T
NIL
> (word-possible-p "abba" '("AB" "AB" "AC" "AC"))
T

## Component Pascal

MODULE ABCProblem;
IMPORT
StdLog, DevCommanders, TextMappers;
CONST
notfound = -1;
TYPE
String = ARRAY 3 OF CHAR;
VAR
blocks : ARRAY 20 OF String;

PROCEDURE Check(s: ARRAY OF CHAR): BOOLEAN;
VAR
used: SET;
i,blockIndex: INTEGER;

PROCEDURE GetBlockFor(c: CHAR): INTEGER;
VAR
i: INTEGER;
BEGIN
c := CAP(c);
i := 0;
WHILE (i < LEN(blocks)) DO
IF (c = blocks[i][0]) OR (c = blocks[i][1]) THEN
IF ~(i IN used) THEN RETURN i END
END;
INC(i)
END;
RETURN notfound
END GetBlockFor;

BEGIN
used := {};
FOR i := 0 TO LEN(s\$) - 1 DO
blockIndex := GetBlockFor(s[i]);
IF blockIndex = notfound THEN
RETURN FALSE
ELSE
INCL(used,blockIndex)
END
END;
RETURN TRUE
END Check;

PROCEDURE CanMakeWord*;
VAR
s: TextMappers.Scanner;
BEGIN
s.ConnectTo(DevCommanders.par.text);
s.SetPos(DevCommanders.par.beg);
s.Scan;
WHILE (~s.rider.eot) DO
IF (s.type = TextMappers.char) & (s.char = '~') THEN
RETURN
ELSIF (s.type = TextMappers.string) THEN
StdLog.String(s.string);StdLog.String(":> ");
StdLog.Bool(Check(s.string));StdLog.Ln
END;
s.Scan
END
END CanMakeWord;

BEGIN
blocks[0] := "BO";
blocks[1] := "XK";
blocks[2] := "DQ";
blocks[3] := "CP";
blocks[4] := "NA";
blocks[5] := "GT";
blocks[6] := "RE";
blocks[7] := "TG";
blocks[8] := "QD";
blocks[9] := "FS";
blocks[10] := "JW";
blocks[11] := "HU";
blocks[12] := "VI";
blocks[13] := "AN";
blocks[14] := "OB";
blocks[15] := "ER";
blocks[16] := "FS";
blocks[17] := "LY";
blocks[18] := "PC";
blocks[19] := "ZM";

END ABCProblem.

Execute: ^Q ABCProblem.CanMakeWord A BARK BOOK TREAT COMMON SQUAD confuse~

Output:
A:>  \$TRUE
BARK:>  \$TRUE
BOOK:>  \$FALSE
TREAT:>  \$TRUE
COMMON:>  \$FALSE
confuse:>  \$TRUE

## Cowgol

include "cowgol.coh";
include "strings.coh";

sub can_make_word(word: [uint8]): (r: uint8) is
var blocks: [uint8] := "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM";

# Initialize blocks array
var avl: uint8[41];
CopyString(blocks, &avl[0]);

r := 1;
loop
var letter := [word];
word := @next word;
if letter == 0 then break; end if;

# find current letter in blocks
var i: @indexof avl := 0;
loop
var block := avl[i];
if block == 0 then
# no block, this word cannot be formed
r := 0;
return;
elseif block == letter then
# we found it, blank it out
avl[i] := ' ';
avl[i^1] := ' '; # and the other letter on the block too
break;
end if;
i := i + 1;
end loop;
end loop;
end sub;

# test a list of words
var words: [uint8][] := {"A","BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"};
var resp: [uint8][] := {": No\n", ": Yes\n"};
var i: @indexof words := 0;
while i < @sizeof words loop
print(words[i]);
print(resp[can_make_word(words[i])]);
i := i + 1;
end loop;
Output:
A: Yes
BARK: Yes
BOOK: No
TREAT: Yes
COMMON: No
CONFUSE: Yes

## D

### Basic Version

Translation of: Python

A simple greedy algorithm is enough for the given sequence of blocks. canMakeWord is true on an empty word because you can compose it using zero blocks.

import std.stdio, std.algorithm, std.string;

bool canMakeWord(in string word, in string[] blocks) pure /*nothrow*/ @safe {
auto bs = blocks.dup;
outer: foreach (immutable ch; word.toUpper) {
foreach (immutable block; bs)
if (block.canFind(ch)) {
bs = bs.remove(bs.countUntil(block));
continue outer;
}
return false;
}
return true;
}

void main() @safe {
immutable blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI
AN OB ER FS LY PC ZM"
.split;

foreach (word; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
writefln(`"%s" %s`, word, canMakeWord(word, blocks));
}
Output:
"" true
"A" true
"BARK" true
"BoOK" false
"TrEAT" true
"COmMoN" false
"conFUsE" true

### @nogc Version

The same as the precedent version, but it avoids all heap allocations and it's lower-level and ASCII-only.

import std.ascii, core.stdc.stdlib;

bool canMakeWord(in string word, in string[] blocks) nothrow @nogc
in {
foreach (immutable char ch; word)
assert(ch.isASCII);
foreach (const block; blocks)
assert(block.length == 2 && block[0].isASCII && block[1].isASCII);
} body {
auto ptr = cast(string*)alloca(blocks.length * string.sizeof);
if (ptr == null)
exit(1);
auto blocks2 = ptr[0 .. blocks.length];
blocks2[] = blocks[];

outer: foreach (immutable i; 0 .. word.length) {
immutable ch = word[i].toUpper;
foreach (immutable j; 0 .. blocks2.length) {
if (blocks2[j][0] == ch || blocks2[j][1] == ch) {
if (blocks2.length > 1)
blocks2[j] = blocks2[\$ - 1];
blocks2 = blocks2[0 .. \$ - 1];
continue outer;
}
}
return false;
}
return true;
}

void main() {
import std.stdio, std.string;

immutable blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI
AN OB ER FS LY PC ZM"
.split;

foreach (word; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
writefln(`"%s" %s`, word, canMakeWord(word, blocks));
}

### Recursive Version

This version is able to find the solution for the word "abba" given the blocks AB AB AC AC.

Translation of: C
import std.stdio, std.ascii, std.algorithm, std.array;

alias Block = char[2];

// Modifies the order of the given blocks.
bool canMakeWord(Block[] blocks, in string word) pure nothrow
in {
assert(blocks.all!(w => w[].all!isAlpha));
assert(word.all!isAlpha);
} body {
if (word.empty)
return true;

immutable c = word[0].toUpper;
foreach (ref b; blocks) {
if (b[0].toUpper != c && b[1].toUpper != c)
continue;
blocks[0].swap(b);
if (blocks[1 .. \$].canMakeWord(word[1 .. \$]))
return true;
blocks[0].swap(b);
}

return false;
}

void main() {
enum Block[] blocks = "BO XK DQ CP NA GT RE TG QD FS
JW HU VI AN OB ER FS LY PC ZM"
.split;

foreach (w; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
writefln(`"%s" %s`, w, blocks.canMakeWord(w));

// Extra test.
Block[] blocks2 = ["AB", "AB", "AC", "AC"];
immutable word = "abba";
writefln(`"%s" %s`, word, blocks2.canMakeWord(word));
}
Output:
"" true
"A" true
"BARK" true
"BoOK" false
"TrEAT" true
"COmMoN" false
"conFUsE" true
"abba" true

### Alternative Recursive Version

This version doesn't shuffle the input blocks, but it's more complex and it allocates an array of indexes.

import std.stdio, std.ascii, std.algorithm, std.array, std.range;

alias Block = char[2];

bool canMakeWord(immutable Block[] blocks, in string word) pure nothrow
in {
assert(blocks.all!(w => w[].all!isAlpha));
assert(word.all!isAlpha);
} body {
bool inner(size_t[] indexes, in string w) pure nothrow {
if (w.empty)
return true;

immutable c = w[0].toUpper;
foreach (ref idx; indexes) {
if (blocks[idx][0].toUpper != c &&
blocks[idx][1].toUpper != c)
continue;
indexes[0].swap(idx);
if (inner(indexes[1 .. \$], w[1 .. \$]))
return true;
indexes[0].swap(idx);
}

return false;
}

return inner(blocks.length.iota.array, word);
}

void main() {
enum Block[] blocks = "BO XK DQ CP NA GT RE TG QD FS
JW HU VI AN OB ER FS LY PC ZM"
.split;

foreach (w; "" ~ "A BARK BoOK TrEAT COmMoN SQUAD conFUsE".split)
writefln(`"%s" %s`, w, blocks.canMakeWord(w));

// Extra test.
immutable Block[] blocks2 = ["AB", "AB", "AC", "AC"];
immutable word = "abba";
writefln(`"%s" %s`, word, blocks2.canMakeWord(word));
}

The output is the same.

## Delphi

Just to be different I implemented a block as a set of (2) char rather than as an array of (2) char.

program ABC;
{\$APPTYPE CONSOLE}

uses SysUtils;

type
TBlock = set of char;

const
TheBlocks : array [0..19] of TBlock =
(
[ 'B', 'O' ], [ 'X', 'K' ], [ 'D', 'Q' ], [ 'C', 'P' ], [ 'N', 'A' ],
[ 'G', 'T' ], [ 'R', 'E' ], [ 'T', 'G' ], [ 'Q', 'D' ], [ 'F', 'S' ],
[ 'J', 'W' ], [ 'H', 'U' ], [ 'V', 'I' ], [ 'A', 'N' ], [ 'O', 'B' ],
[ 'E', 'R' ], [ 'F', 'S' ], [ 'L', 'Y' ], [ 'P', 'C' ], [ 'Z', 'M' ]
);

function SolveABC(Target : string; Blocks : array of TBlock) : boolean;
var
iChr : integer;
Used : array [0..19] of boolean;

function FindUnused(TargetChr : char) : boolean; // Nested routine
var
iBlock : integer;
begin
Result := FALSE;
for iBlock := low(Blocks) to high(Blocks) do
if (not Used[iBlock]) and ( TargetChr in Blocks[iBlock] ) then
begin
Result := TRUE;
Used[iBlock] := TRUE;
Break;
end;
end;

begin
FillChar(Used, sizeof(Used), ord(FALSE));
Result := TRUE;
iChr := 1;
while Result and (iChr <= length(Target)) do
if FindUnused(Target[iChr]) then inc(iChr)
else Result := FALSE;
end;

procedure CheckABC(Target : string);
begin
if SolveABC(uppercase(Target), TheBlocks) then
writeln('Can make ' + Target)
else
writeln('Can NOT make ' + Target);
end;

begin
CheckABC('A');
CheckABC('BARK');
CheckABC('BOOK');
CheckABC('TREAT');
CheckABC('COMMON');
CheckABC('CONFUSE');
end.

Output:
Output:
Can make A
Can make BARK
Can NOT make BOOK
Can make TREAT
Can NOT make COMMON
Can make CONFUSE

## Draco

\util.g

proc nonrec ucase(char c) char:
byte b;
b := pretend(c, byte);
b := b & ~32;
pretend(b, char)
corp

proc nonrec can_make_word(*char w) bool:
[41] char blocks;
word i;
char ch;
bool found, ok;

CharsCopy(&blocks[0], "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM");

ok := true;
while
ch := ucase(w*);
w := w + 1;
ok and ch ~= '\e'
do
found := false;
i := 0;
while not found and i < 40 do
if blocks[i] = ch then found := true fi;
i := i + 1;
od;
if found then
i := i - 1;
blocks[i] := '\e';
blocks[i >< 1] := '\e'
else
ok := false
fi
od;
ok
corp

proc nonrec test(*char w) void:
writeln(w, ": ", if can_make_word(w) then "yes" else "no" fi)
corp

proc nonrec main() void:
test("A");
test("BARK");
test("book");
test("treat");
test("CoMmOn");
test("CONFUSE")
corp
Output:
A: yes
BARK: yes
book: no
treat: yes
CoMmOn: no
CONFUSE: yes

## Dyalect

Translation of: Swift
func blockable(str) {
var blocks = [
"BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM" ]

var strUp = str.Upper()
var fin = ""

for c in strUp {
for j in blocks.Indices() {
if blocks[j].StartsWith(c) || blocks[j].EndsWith(c) {
fin += c
blocks[j] = ""
break
}
}
}

return fin == strUp
}

func canOrNot(can) => can ? "can" : "cannot"

for str in [ "A", "BARK", "BooK", "TrEaT", "comMON", "sQuAd", "Confuse" ] {
print("\"\(str)\" \(canOrNot(blockable(str))) be spelled with blocks.")
}
Output:
"A" can be spelled with blocks.
"BARK" can be spelled with blocks.
"BooK" cannot be spelled with blocks.
"TrEaT" can be spelled with blocks.
"comMON" cannot be spelled with blocks.
"sQuAd" can be spelled with blocks.
"Confuse" can be spelled with blocks.

## EchoLisp

(lib 'list) ;; list-delete

(define BLOCKS '("BO" "XK" "DQ" "CP" "NA" "GT" "RE" "TG" "QD" "FS"
"JW" "HU" "VI" "AN" "OB" "ER" "FS" "LY" "PC" "ZM" ))

(define WORDS '("A" "BARK" "BOOK" "TREAT" "COMMON" "SQUAD" "CONFUSE"))

(define (spell word blocks)
(cond
((string-empty? word) #t)
((empty? blocks) #f)
(else
(for/or [(block blocks)]
#:continue (not (string-match block (string-first word)))
(spell (string-rest word) (list-delete blocks block))))))

Output:
(for ((w WORDS))
(writeln
(string-randcase w)
(spell (string-upcase w) BLOCKS)))

A     #t
bARK     #t
BooK     #f
TReAt     #t
ComMOn     #f
COnfUSe     #t

## Ela

open list monad io char

:::IO

null = foldr (\_ _ -> false) true

mapM_ f = foldr ((>>-) << f) (return ())

abc _ [] = [[]]
abc blocks (c::cs) =
[b::ans \\ b <- blocks | c `elem` b, ans <- abc (delete b blocks) cs]

blocks = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]

mapM_ (\w -> putLn (w, not << null \$ abc blocks (map char.upper w)))
["", "A", "BARK", "BoOK", "TrEAT", "COmMoN", "SQUAD", "conFUsE"]
Output:
("conFUsE",true)
("COmMoN",false)
("TrEAT",true)
("BoOK",false)
("BARK",true)
("A",true)
("",true)

## Elena

ELENA 5.0

import system'routines;
import system'collections;
import extensions;
import extensions'routines;

extension op
{
canMakeWordFrom(blocks)
{
var list := ArrayList.load(blocks);

^ nil == (cast string(self)).upperCase().seekEach:(ch)
{
var index := list.indexOfElement
((word => word.indexOf(0, ch) != -1).asComparator());

if (index>=0)
{
list.removeAt(index); ^ false
}
else
{
^ true
}
}
}
}

public program()
{
var blocks := new string[]{"BO", "XK", "DQ", "CP", "NA",
"GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB",
"ER", "FS", "LY", "PC", "ZM"};

var words := new string[]{"", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse"};

Enumerator e := words.enumerator();
e.next();

words.forEach:(word)
{
console.printLine("can make '",word,"' : ",word.canMakeWordFrom(blocks));
}
}
Output:
can make '' : true
can make 'A' : true
can make 'BARK' : true
can make 'BOOK' : false
can make 'TREAT' : true
can make 'COMMON' : false
can make 'SQUAD' : true
can make 'Confuse' : true

## Elixir

Translation of: Erlang
Works with: Elixir version 1.3
defmodule ABC do
def can_make_word(word, avail) do
can_make_word(String.upcase(word) |> to_charlist, avail, [])
end

defp can_make_word([], _, _), do: true
defp can_make_word(_, [], _), do: false
defp can_make_word([l|tail], [b|rest], tried) do
(l in b and can_make_word(tail, rest++tried, []))
or can_make_word([l|tail], rest, [b|tried])
end
end

blocks = ~w(BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM)c
~w(A Bark Book Treat Common Squad Confuse) |>
Enum.map(fn(w) -> IO.puts "#{w}: #{ABC.can_make_word(w, blocks)}" end)
Output:
A: true
Bark: true
Book: false
Treat: true
Common: false
Confuse: true

## Erlang

-module(abc).
-export([can_make_word/1, can_make_word/2, blocks/0]).

blocks() -> ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"].

can_make_word(Word) -> can_make_word(Word, blocks()).
can_make_word(Word, Avail) -> can_make_word(string:to_upper(Word), Avail, []).
can_make_word([], _, _) -> true;
can_make_word(_, [], _) -> false;
can_make_word([L|Tail], [B|Rest], Tried) ->
(lists:member(L,B) andalso can_make_word(Tail, lists:append(Rest, Tried),[]))
orelse can_make_word([L|Tail], Rest, [B|Tried]).

main(_) -> lists:map(fun(W) -> io:fwrite("~s: ~s~n", [W, can_make_word(W)]) end,

Output:
A: true
Bark: true
Book: false
Treat: true
Common: false
Confuse: true

## ERRE

PROGRAM BLOCKS

!\$INCLUDE="PC.LIB"

PROCEDURE CANMAKEWORD(WORD\$)
LOCAL B\$,P%
B\$=BLOCKS\$
PRINT(WORD\$;" -> ";)
P%=INSTR(B\$,CHR\$(ASC(WORD\$) AND \$DF))
WHILE P%>0 AND WORD\$>"" DO
CHANGE(B\$,P%-1+(P% MOD 2),".."->B\$)
WORD\$=MID\$(WORD\$,2)
EXIT IF WORD\$=""
P%=INSTR(B\$,CHR\$(ASC(WORD\$) AND \$DF))
END WHILE
IF WORD\$>"" THEN PRINT("False") ELSE PRINT("True") END IF
END PROCEDURE

BEGIN
BLOCKS\$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
CANMAKEWORD("A")
CANMAKEWORD("BARK")
CANMAKEWORD("BOOK")
CANMAKEWORD("TREAT")
CANMAKEWORD("COMMON")
CANMAKEWORD("Confuse")
END PROGRAM

## Euphoria

implemented using OpenEuphoria

include std/text.e

sequence blocks = {{'B','O'},{'X','K'},{'D','Q'},{'C','P'},{'N','A'},
{'G','T'},{'R','E'},{'T','G'},{'Q','D'},{'F','S'},
{'J','W'},{'H','U'},{'V','I'},{'A','N'},{'O','B'},
{'E','R'},{'F','S'},{'L','Y'},{'P','C'},{'Z','M'}}
sequence words = {"A","BarK","BOOK","TrEaT","COMMON","SQUAD","CONFUSE"}

sequence current_word
sequence temp
integer matches

for i = 1 to length(words) do
current_word = upper(words[i])
temp = blocks
matches = 0
for j = 1 to length(current_word) do
for k = 1 to length(temp) do
if find(current_word[j],temp[k]) then
temp = remove(temp,k)
matches += 1
exit
end if
end for
if length(current_word) = matches then
printf(1,"%s: TRUE\n",{words[i]})
exit
end if
end for
if length(current_word) != matches then
printf(1,"%s: FALSE\n",{words[i]})
end if
end for

if getc(0) then end if

Output:
A: TRUE
BarK: TRUE
BOOK: FALSE
TrEaT: TRUE
COMMON: FALSE
CONFUSE: TRUE

..press Enter..

## F#

This solution does not depend on the order of the blocks, neither on the symmetry of blocks we see in the example block set. (Symmetry: if AB is a block, an A comes only with another AB|BA)

let rec spell_word_with blocks w =
let rec look_for_right_candidate candidates noCandidates c rest =
match candidates with
| [] -> false
| c0::cc ->
if spell_word_with ([email protected]) rest then true
else look_for_right_candidate cc (c0::noCandidates) c rest

match w with
| "" -> true
| w ->
let c = w.[0]
let rest = w.Substring(1)
let (candidates, noCandidates) = List.partition(fun (c1,c2) -> c = c1 || c = c2) blocks
look_for_right_candidate candidates noCandidates c rest

[<EntryPoint>]
let main argv =
let default_blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
let blocks =
(if argv.Length > 0 then argv.[0] else default_blocks).Split()
|> List.ofArray
|> List.map(fun s -> s.ToUpper())
|> List.map(fun s2 -> s2.[0], s2.[1])
let words =
(if argv.Length > 0 then List.ofArray(argv).Tail else [])
|> List.map(fun s -> s.ToUpper())

List.iter (fun w -> printfn "Using the blocks we can make the word '%s': %b" w (spell_word_with blocks w)) words
0
Output:
h:\RosettaCode\ABC\Fsharp>RosettaCode "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM" a bark book threat common squad confuse
Using the blocks we can make the word 'A': true
Using the blocks we can make the word 'BARK': true
Using the blocks we can make the word 'BOOK': false
Using the blocks we can make the word 'THREAT': true
Using the blocks we can make the word 'COMMON': false
Using the blocks we can make the word 'SQUAD': true
Using the blocks we can make the word 'CONFUSE': true

h:\RosettaCode\ABC\Fsharp>RosettaCode  "aB aB Ac Ac" abba
Using the blocks we can make the word 'ABBA': true

h:\RosettaCode\ABC\Fsharp>RosettaCode "US TZ AO QA" Auto
Using the blocks we can make the word 'AUTO': true

## Factor

USING: assocs combinators.short-circuit formatting grouping io
kernel math math.statistics qw sequences sets unicode ;
IN: rosetta-code.abc-problem

! === CONSTANTS ================================================

CONSTANT: blocks qw{
BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
}

CONSTANT: input qw{ A BARK BOOK TREAT COMMON SQUAD CONFUSE }

! === PROGRAM LOGIC ============================================

: pare ( str -- seq )
[ blocks ] dip [ intersects? ] curry filter ;

: enough-blocks? ( str -- ? ) dup pare [ length ] [email protected] <= ;

: enough-letters? ( str -- ? )
[ blocks concat ] dip dup [ within ] dip
[ histogram values ] [email protected] [ - ] 2map [ neg? ] any? not ;

: can-make-word? ( str -- ? )
>upper { [ enough-blocks? ] [ enough-letters? ] } 1&& ;

! === OUTPUT ===================================================

: show-blocks ( -- )
"Available blocks:" print blocks [ 1 cut "(%s %s)" sprintf ]
map 5 group [ [ write bl ] each nl ] each nl ;

: header ( -- )
"Word" "Can make word from blocks?" "%-7s %s\n" printf
"======= ==========================" print ;

: result ( str -- )
dup can-make-word? "Yes" "No" ? "%-7s %s\n" printf ;

! === MAIN =====================================================

: abc-problem ( -- )
show-blocks header input [ result ] each ;

MAIN: abc-problem
Output:
Available blocks:
(B O) (X K) (D Q) (C P) (N A)
(G T) (R E) (T G) (Q D) (F S)
(J W) (H U) (V I) (A N) (O B)
(E R) (F S) (L Y) (P C) (Z M)

Word    Can make word from blocks?
======= ==========================
A       Yes
BARK    Yes
BOOK    No
TREAT   Yes
COMMON  No
CONFUSE Yes

## FBSL

This approach uses a string, blanking out the pair previously found. Probably faster than array manipulation.

#APPTYPE CONSOLE
SUB MAIN()
BlockCheck("A")
BlockCheck("BARK")
BlockCheck("BooK")
BlockCheck("TrEaT")
BlockCheck("comMON")
BlockCheck("Confuse")
pause
END SUB

FUNCTION BlockCheck(str)
PRINT str " " iif( Blockable( str ), "can", "cannot" ) " be spelled with blocks."
END FUNCTION

FUNCTION Blockable(str AS STRING)
DIM blocks AS STRING = "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
DIM C AS STRING = ""
DIM POS AS INTEGER = 0

FOR DIM I = 1 TO LEN(str)
C = str{i}
POS = INSTR(BLOCKS, C, 0, 1) 'case insensitive
IF POS > 0 THEN
'if the pos is odd, it's the first of the pair
IF POS MOD 2 = 1 THEN
'so clear the first and the second
POKE(@blocks + POS - 1," ")
POKE(@blocks + POS," ")
'otherwise, it's the last of the pair
ELSE
'clear the second and the first
POKE(@blocks + POS - 1," ")
POKE(@blocks + POS - 2," ")
END IF
ELSE
RETURN FALSE
END IF
NEXT
'got thru to here, so can be spelled
RETURN TRUE
END FUNCTION

Output:
A can be spelled with blocks.
BARK can be spelled with blocks.
BooK cannot be spelled with blocks.
TrEaT can be spelled with blocks.
comMON cannot be spelled with blocks.
sQuAd can be spelled with blocks.
Confuse can be spelled with blocks.

Press any key to continue...

## Forth

Works with: gforth version 0.7.3
: blockslist s" BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM" ;
variable blocks
: allotblocks ( -- ) here blockslist dup allot here over - swap move blocks ! ;
: freeblocks blockslist nip negate allot ;
: toupper 223 and ;

: clearblock ( addr-block -- )
dup '_' swap c!
dup blocks @ - 1 and if 1- else 1+ then
'_' swap c!
;

: pickblock ( addr-input -- addr-input+1 f )
dup 1+ swap [email protected] toupper ( -- addr-input+1 c )
blockslist nip 0 do
blocks @ i + dup [email protected] 2 pick ( -- addr-input+1 c addri ci c )
= if clearblock drop true unloop exit else drop then
loop drop false
;

: abc ( addr-input u -- f )
allotblocks
0 do
pickblock
invert if drop false unloop exit cr then
loop drop true
freeblocks
;

: .abc abc if ." True" else ." False" then ;
Output:
s" A" .abc True ok
s" BarK" .abc True ok
s" BOOK" .abc False ok
s" TrEaT" .abc True ok
s" COMMON" .abc False ok
s" SQUAD" .abc True ok
s" CONFUSE" .abc True ok

## Fortran

Attempts to write the word read from unit 5. Please find the output, bash command, and gfortran compilation instructions as commentary at the start of the source, which starts right away!

!-*- mode: compilation; default-directory: "/tmp/" -*-
!Compilation started at Thu Jun 5 01:52:03
!
!make f && for a in '' a bark book treat common squad confuse ; do echo \$a | ./f ; done
!gfortran -std=f2008 -Wall -fopenmp -ffree-form -fall-intrinsics -fimplicit-none -g f.f08 -o f
! T
! T A NA
! T BARK BO NA RE XK
! F BOOK OB BO -- --
! T TREAT GT RE ER NA TG
! F COMMON PC OB ZM -- -- --
! T SQUAD FS DQ HU NA QD
! T CONFUSE CP BO NA FS HU FS RE
!
!Compilation finished at Thu Jun 5 01:52:03

program abc
implicit none
integer, parameter :: nblocks = 20
character(len=nblocks) :: goal
integer, dimension(nblocks) :: solution
character(len=2), dimension(0:nblocks) :: blocks_copy, blocks = &
&(/'--','BO','XK','DQ','CP','NA','GT','RE','TG','QD','FS','JW','HU','VI','AN','OB','ER','FS','LY','PC','ZM'/)
logical :: valid
integer :: i, iostat
if (iostat .ne. 0) goal = ''
call ucase(goal)
solution = 0
blocks_copy = blocks
valid = assign_block(goal(1:len_trim(goal)), blocks, solution, 1)
write(6,*) valid, ' '//goal, (' '//blocks_copy(solution(i)), i=1,len_trim(goal))

contains

recursive function assign_block(goal, blocks, solution, n) result(valid)
implicit none
logical :: valid
character(len=*), intent(in) :: goal
character(len=2), dimension(0:), intent(inout) :: blocks
integer, dimension(:), intent(out) :: solution
integer, intent(in) :: n
integer :: i
character(len=2) :: backing_store
valid = .true.
if (len(goal)+1 .eq. n) return
do i=1, size(blocks)
if (index(blocks(i),goal(n:n)) .ne. 0) then
backing_store = blocks(i)
blocks(i) = ''
solution(n) = i
if (assign_block(goal, blocks, solution, n+1)) return
blocks(i) = backing_store
end if
end do
valid = .false.
return
end function assign_block

subroutine ucase(a)
implicit none
character(len=*), intent(inout) :: a
integer :: i, j
do i = 1, len_trim(a)
j = index('abcdefghijklmnopqrstuvwxyz',a(i:i))
if (j .ne. 0) a(i:i) = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'(j:j)
end do
end subroutine ucase

end program abc

### But if backtracking might be needed

The example set does not exercise the possible need for backtracking, as when an initial selection of blocks prevents completion because available letters have been used up. This can only arise when the same letter appears on more than one block and does so with different partners. The example set does contain duplicated letters, but they appear only via blocks with the same letters. Suppose instead that the block collection was AB, BC, CD, ... XY, YZ so that every letter appears twice except for A and Z. If the target word was STOPPED then both OP and PQ would be needed to supply P, but if the O had been supplied via OP then the second P would be unavailable. If instead the O were to be supplied by NO then all would be well.

The method involves the stack-style usage of array MOVE, but there is no explicit attempt at recursion. The array contains the possible moves at each level, and if necessary, a move made can later be retracted and an alternative sought. This is the standard style of playing board games such as chess via developing a "game tree", but in this case the tree traversal is not a large task.

The following source begins with some support routines. Subroutine PLAY inspects the collection of blocks to make various remarks, and function CANBLOCK reports on whether a word can be spelled out with the supplied blocks. The source requires only a few of the F90 features. The MODULE protocol eases communication, but the key feature is that subprograms can now declare arrays of a size determined on entry via parameters. Previously, a constant with the largest-possible size would be required.

MODULE PLAYPEN !Messes with a set of alphabet blocks.
INTEGER MSG !Output unit number.
PARAMETER (MSG = 6) !Standard output.
INTEGER MS !I dislike unidentified constants...
PARAMETER (MS = 2) !So this is the maximum number of lettered sides.
INTEGER LETTER(26),SUPPLY(26) !For counting the alphabet.
CONTAINS
SUBROUTINE SWAP(I,J) !This really should be known to the compiler.
INTEGER I,J,K !Which could generate in-place code,
K = I !Using registers, maybe.
I = J !Or maybe, there are special op-codes.
J = K !Rather than this clunkiness.
END SUBROUTINE SWAP !And it should be for any type of thingy.

INTEGER FUNCTION LSTNB(TEXT) !Sigh. Last Not Blank.
Concocted yet again by R.N.McLean (whom God preserve) December MM.
Code checking reveals that the Compaq compiler generates a copy of the string and then finds the length of that when using the latter-day intrinsic LEN_TRIM. Madness!
Can't DO WHILE (L.GT.0 .AND. TEXT(L:L).LE.' ') !Control chars. regarded as spaces.
Curse the morons who think it good that the compiler MIGHT evaluate logical expressions fully.
Crude GO TO rather than a DO-loop, because compilers use a loop counter as well as updating the index variable.
Comparison runs of GNASH showed a saving of ~3% in its mass-data reading through the avoidance of DO in LSTNB alone.
Crappy code for character comparison of varying lengths is avoided by using ICHAR which is for single characters only.
Checking the indexing of CHARACTER variables for bounds evoked astounding stupidities, such as calculating the length of TEXT(L:L) by subtracting L from L!
Comparison runs of GNASH showed a saving of ~25-30% in its mass data scanning for this, involving all its two-dozen or so single-character comparisons, not just in LSTNB.
CHARACTER*(*),INTENT(IN):: TEXT !The bumf. If there must be copy-in, at least there need not be copy back.
INTEGER L !The length of the bumf.
L = LEN(TEXT) !So, what is it?
1 IF (L.LE.0) GO TO 2 !Are we there yet?
IF (ICHAR(TEXT(L:L)).GT.ICHAR(" ")) GO TO 2 !Control chars are regarded as spaces also.
L = L - 1 !Step back one.
GO TO 1 !And try again.
2 LSTNB = L !The last non-blank, possibly zero.
RETURN !Unsafe to use LSTNB as a variable.
END FUNCTION LSTNB !Compilers can bungle it.

SUBROUTINE LETTERCOUNT(TEXT) !Count the occurrences of A-Z.
CHARACTER*(*) TEXT !The text to inspect.
INTEGER I,K !Assistants.
DO I = 1,LEN(TEXT) !Step through the text.
K = ICHAR(TEXT(I:I)) - ICHAR("A") + 1 !This presumes that A-Z have contiguous codes!
IF (K.GE.1 .AND. K.LE.26) LETTER(K) = LETTER(K) + 1 !Not so with EBCDIC!!
END DO !On to the next letter.
END SUBROUTINE LETTERCOUNT !Be careful with LETTER.

SUBROUTINE UPCASE(TEXT) !In the absence of an intrinsic...
Converts any lower case letters in TEXT to upper case...
Concocted yet again by R.N.McLean (whom God preserve) December MM.
Converting from a DO loop evades having both an iteration counter to decrement and an index variable to adjust.
CHARACTER*(*) TEXT !The stuff to be modified.
c CHARACTER*26 LOWER,UPPER !Tables. a-z may not be contiguous codes.
c PARAMETER (LOWER = "abcdefghijklmnopqrstuvwxyz")
c PARAMETER (UPPER = "ABCDEFGHIJKLMNOPQRSTUVWXYZ")
CAREFUL!! The below relies on a-z and A-Z being contiguous, as is NOT the case with EBCDIC.
INTEGER I,L,IT !Fingers.
L = LEN(TEXT) !Get a local value, in case LEN engages in oddities.
I = L !Start at the end and work back..
1 IF (I.LE.0) RETURN !Are we there yet? Comparison against zero should not require a subtraction.
c IT = INDEX(LOWER,TEXT(I:I)) !Well?
c IF (IT .GT. 0) TEXT(I:I) = UPPER(IT:IT) !One to convert?
IT = ICHAR(TEXT(I:I)) - ICHAR("a") !More symbols precede "a" than "A".
IF (IT.GE.0 .AND. IT.LE.25) TEXT(I:I) = CHAR(IT + ICHAR("A")) !In a-z? Convert!
I = I - 1 !Back one.
GO TO 1 !Inspect..
END SUBROUTINE UPCASE !Easy.

SUBROUTINE ORDERSIDE(LETTER) !Puts the letters into order.
CHARACTER*(*) LETTER !The letters.
INTEGER I,N,H !Assistants.
CHARACTER*1 T !A scratchpad.
LOGICAL CURSE !A bit.
N = LEN(LETTER) !So, how many letters?
H = N - 1 !Last - First, and not +1.
IF (H.LE.0) RETURN !Ha ha.
1 H = MAX(1,H*10/13) !The special feature.
IF (H.EQ.9 .OR. H.EQ.10) H = 11 !A twiddle.
CURSE = .FALSE. !So far, so good.
DO I = N - H,1,-1 !If H = 1, this is a BubbleSort.
IF (LETTER(I:I).LT.LETTER(I + H:I + H)) THEN !One compare.
T = LETTER(I:I) !One swap.
LETTER(I:I) = LETTER(I + H:I + H) !Alas, no SWAP(A,B)
LETTER(I + H:I + H) = T !Is recognised by the compiler.
CURSE = .TRUE. !If once a tiger is seen...
END IF !So much for that comparison.
END DO !On to the next.
IF (CURSE .OR. H.GT.1) GO TO 1!Another pass?
END SUBROUTINE ORDERSIDE !Simple enough.
SUBROUTINE ORDERBLOCKS(N,SOME) !Puts the collection of blocks into order.
INTEGER N !The number of blocks.
CHARACTER*(*) SOME(:) !Their lists of letters.
INTEGER I,H !Assistants.
CHARACTER*(LEN(SOME(1))) T !A scratchpad matching an element of SOME.
LOGICAL CURSE !Since there is still no SWAP(SOME(I),SOME(I + H)).
H = N - 1 !So here comes another CombSort.
IF (H.LE.0) RETURN !With standard suspicion.
1 H = MAX(1,H*10/13) !This is the outer loop.
IF (H.EQ.9 .OR. H.EQ.10) H = 11 !This is a fiddle.
CURSE = .FALSE. !Start the next pass in hope.
DO I = N - H,1,-1 !Going backwards, just for fun.
IF (SOME(I).LT.SOME(I + H)) THEN !So then?
T = SOME(I) !Disorder.
SOME(I) = SOME(I + H) !So once again,
SOME(I + H) = T !Swap the two miscreants.
CURSE = .TRUE. !And remember.
END IF !So much for that comparison.
END DO !On to the next.
IF (CURSE .OR. H.GT.1) GO TO 1!Are we there yet?
END SUBROUTINE ORDERBLOCKS !Not much code, but ringing the changes is still tedious.

SUBROUTINE PLAY(N,SOME) !Mess about with the collection of blocks.
INTEGER N !Their number.
CHARACTER*(*) SOME(:) !Their letters.
INTEGER NH,HIT(N) !A list of blocks.
INTEGER B,I,J,K,L,M !Assistants.
CHARACTER*1 C !A letter of the moment.
L = LEN(SOME(1)) !The maximum number of letters to any block.
Cast the collection on to the floor.
WRITE (MSG,1) N,L,SOME !Announce the set as it is supplied.
1 FORMAT (I7," blocks, with at most",I2," letters:",66(1X,A))
Change the "orientation" of some blocks.
DO B = 1,N !Step through each block.
CALL UPCASE(SOME(B)) !Paranoia rules.
CALL ORDERSIDE(SOME(B)) !Put its letter list into order.
END DO !On to the next block.
WRITE (MSG,2) SOME !Reveal the orderly array.
2 FORMAT (6X,"... the letters in reverse order:",66(1X,A))
Collate the collection of blocks.
CALL ORDERBLOCKS(N,SOME) !Now order the blocks by their letters.
WRITE (MSG,3) SOME !Reveal them in neato order.
3 FORMAT (7X,"... the blocks in reverse order:",66(1X,A))
Count the appearances of the letters of the alphabet.
LETTER = 0 !Enough of shuffling blocks around.
DO B = 1,N !Now inspect their collective letters.
CALL LETTERCOUNT(SOME(B)) !A block's worth at a go.
END DO !On to the next block.
SUPPLY = LETTER !Save the counts of supplied letters.
WRITE (MSG,4) (CHAR(ICHAR("A") + I - 1),I = 1,26),SUPPLY !Results.
4 FORMAT (15X,"Letters of the alphabet:",26A<MS + 1>,/, !First, a line with A ... Z.
1 11X,"... number thereof supplied:",26I<MS + 1>) !Then a line of the associated counts.
Check for blocks with duplicated letters.
WRITE (MSG,5) !Announce.
5 FORMAT (8X,"Blocks with duplicated letters:",\$) !Further output impends.
M = 0 !No duplication found.
DO B = 1,N !So step through each block.
JJ:DO J = 2,L !Inspecting successive letters of the block,
IF (SOME(B)(J:J).LE." ") EXIT JJ !Provided they've not run out.
DO K = 1,J - 1 !To see if it has appeared earlier.
IF (SOME(B)(K:K).LE." ") EXIT JJ!Reverse order means that spaces will be at the end!
IF (SOME(B)(J:J).EQ.SOME(B)(K:K)) THEN !Well?
M = M + 1 !A match!
WRITE (MSG,6) SOME(B) !Name the block.
6 FORMAT (1X,A,\$) !With further output still impending,
EXIT JJ !And give up on this block.
END IF !One duplicated letter is sufficient for its downfall.
END DO !Next letter up.
END DO JJ !On to the next letter of the block.
END DO !On to the next block.
CALL HIC(M) !Show the count and end the line.
Check for duplicate blocks, knowing that the array of blocks is ordered.
WRITE (MSG,7) !Announce.
7 FORMAT (21X,"Duplicated blocks:",\$) !Again, leave the line dangling.
K = 0 !No duplication found.
B = 1 !Syncopation.
70 B = B + 1 !Advance one.
IF (B.GT.N) GO TO 72 !Are we there yet?
IF (SOME(B).NE.SOME(B - 1)) GO TO 70 !No match? Search on.
K = K + 1 !A match is counted.
WRITE (MSG,6) SOME(B) !Name it.
71 B = B + 1 !And speed through continued matching.
IF (B.GT.N) GO TO 72 !Unless we're of the end.
IF (SOME(B).EQ.SOME(B - 1)) GO TO 71 !Continued matching?
GO TO 70 !Mismatch: resume the normal scan.
72 CALL HIC(K) !So much for that.
Check for duplicated letters across different blocks.
IF (ALL(SUPPLY.LE.1)) RETURN !Unless there are no duplicated letters.
WRITE (MSG,8) !Announce.
8 FORMAT ("Duplicated letters on different blocks:",\$) !More to come.
K = 0 !Start another count.
DO I = 1,26 !A well-known span.
IF (SUPPLY(I).LE.1) CYCLE !Any duplicated letters?
C = CHAR(ICHAR("A") + I - 1)!Yes. This is the character.
NH = 0 !So, how many blocks contribute?
DO B = 1,N !Find out.
IF (INDEX(SOME(B),C).GT.0) THEN !On this block?
NH = NH + 1 !Yes.
HIT(NH) = B !Keep track of which.
END IF !So much for that block.
END DO !On to the next.
IF (ANY(SOME(HIT(2:NH)) .NE. SOME(HIT(1)))) THEN !All have the same collection of letters?
K = K + 1 !No!
WRITE (MSG,9) C !Name the heterogenously supported letter.
9 FORMAT (A<MS + 1>,\$) !Use the same spacing even though one character only.
END IF !So much for that letter's search.
END DO !On to the next letter.
CALL HIC(K) !Finish the line with the count report.
CONTAINS !This is used often enough.
SUBROUTINE HIC(N) !But has very specific context.
INTEGER N !The count.
IF (N.LE.0) WRITE (MSG,*) "None." !Yes, we have no bananas.
IF (N.GT.0) WRITE (MSG,*) N !Either way, end the line.
END SUBROUTINE HIC !This service routine is not needed elsewhere.
END SUBROUTINE PLAY !Look mummy! All the blockses are neatened!

LOGICAL FUNCTION CANBLOCK(WORD,N,SOME) !Can the blocks spell out the word?
Creates a move tree based on the letters of WORD and for each, the blocks available.
CHARACTER*(*) WORD !The word to spell out.
INTEGER N !The number of blocks.
CHARACTER*(*) SOME(:) !The blocks and their letters.
INTEGER NA,AVAIL(N) !Say not the struggle naught availeth!
INTEGER NMOVE(LEN(WORD)) !I need a list of acceptable blocks,
INTEGER MOVE(LEN(WORD),N) !One list for each letter of WORD.
INTEGER I,L,S !Assistants.
CHARACTER*1 C !The letter of the moment.
CANBLOCK = .FALSE. !Initial pessimism.
L = LSTNB(WORD) !Ignore trailing spaces.
IF (L.GT.N) RETURN !Enough blocks?
LETTER = 0 !To make rabbit stew,
CALL LETTERCOUNT(WORD(1:L)) !First catch your rabbit.
IF (ANY(SUPPLY .LT. LETTER)) RETURN !The larder is lacking.
NA = N !Prepare a list.
FORALL (I = 1:N) AVAIL(I) = I !That fingers every block.
I = 0 !Step through the letters of the WORD.
Chug through the letters of the WORD.
1 I = I + 1 !One letter after the other.
IF (I.GT.L) GO TO 100 !Yay! We're through!
C = WORD(I:I) !The letter of the moment.
NMOVE(I) = 0 !No moves known at this new level.
DO S = 1,NA !So, look for them amongst the available slots.
IF (INDEX(SOME(AVAIL(S)),C) .GT. 0) THEN !A hit?
NMOVE(I) = NMOVE(I) + 1 !Yes! Count up another possible move.
MOVE(I,NMOVE(I)) = S !Remember its slot.
END IF !So much for that block.
END DO !On to the next.
2 IF (NMOVE(I).GT.0) THEN !Have we any moves?
S = MOVE(I,NMOVE(I)) !Yes! Recover the last found.
NMOVE(I) = NMOVE(I) - 1 !Uncount, as it is about to be used.
IF (S.NE.NA) CALL SWAP(AVAIL(S),AVAIL(NA)) !This block is no longer available.
NA = NA - 1 !Shift the boundary back.
GO TO 1 !Try the next letter!
END IF !But if we can't find a move at that level...
I = I - 1 !Retreat a level.
IF (I.LE.0) RETURN !Oh dear!
S = MOVE(I,NMOVE(I) + 1) !Undo the move that had been made at this level.
NA = NA + 1 !And make its block is re-available.
IF (S.NE.NA) CALL SWAP(AVAIL(S),AVAIL(NA)) !Move it back.
GO TO 2 !See what moves remain at this level.
Completed!
100 CANBLOCK = .TRUE. !That's a relief.
END FUNCTION CANBLOCK !Some revisions might have been made.
END MODULE PLAYPEN !No sand here.

USE PLAYPEN !Just so.
INTEGER HAVE,TESTS !Parameters for the specified problem.
PARAMETER (HAVE = 20, TESTS = 7) !Number of blocks, number of tests.
CHARACTER*(MS) BLOCKS(HAVE) !Have blocks, will juggle.
DATA BLOCKS/"BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS", !The specified set
1 "JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"/ !Of letter blocks.
CHARACTER*8 WORD(TESTS) !Now for the specified test words.
LOGICAL ANS(TESTS),T,F !And the given results.
PARAMETER (T = .TRUE., F = .FALSE.) !Enable a more compact specification.
DATA WORD/"A","BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"/ !So that these
DATA ANS/ T , T , F , T , F , T , T / !Can be aligned.
LOGICAL YAY
INTEGER I

WRITE (MSG,1)
1 FORMAT ("Arranges alphabet blocks, attending only to the ",
1 "letters on the blocks, and ignoring case and orientation.",/)

CALL PLAY(HAVE,BLOCKS) !Some fun first.

WRITE (MSG,'(/"Now to see if some words can be spelled out.")')
DO I = 1,TESTS
CALL UPCASE(WORD(I))
YAY = CANBLOCK(WORD(I),HAVE,BLOCKS)
WRITE (MSG,*) YAY,ANS(I),YAY.EQ.ANS(I),WORD(I)
END DO
END

Output: the first column of T/F is the report from CANBLOCK, the second is the expected answer from the example, and the third is whether the two are in agreement.

Arranges alphabet blocks, attending only to the letters on the blocks, and ignoring case and orientation.

20 blocks, with at most 2 letters: BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
... the letters in reverse order: OB XK QD PC NA TG RE TG QD SF WJ UH VI NA OB RE SF YL PC ZM
... the blocks in reverse order: ZM YL XK WJ VI UH TG TG SF SF RE RE QD QD PC PC OB OB NA NA
Letters of the alphabet:  A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z
... number thereof supplied:  2  2  2  2  2  2  2  1  1  1  1  1  1  2  2  2  2  2  2  2  1  1  1  1  1  1
Blocks with duplicated letters: None.
Duplicated blocks: TG SF RE QD PC OB NA           7
Duplicated letters on different blocks: None.

Now to see if some words can be spelled out.
T T T A
T T T BARK
F F T BOOK
T T T TREAT
F F T COMMON
T T T SQUAD
T T T CONFUSE

## FreeBASIC

' version 28-01-2019
' compile with: fbc -s console

Dim As String blocks(1 To 20, 1 To 2) => {{"B", "O"}, {"X", "K"}, {"D", "Q"}, _
{"C", "P"}, {"N", "A"}, {"G", "T"}, {"R", "E"}, {"T", "G"}, {"Q", "D"}, _
{"F", "S"}, {"J", "W"}, {"H", "U"}, {"V", "I"}, {"A", "N"}, {"O", "B"}, _
{"E", "R"}, {"F", "S"}, {"L", "Y"}, {"P", "C"}, {"Z", "M"}}

Dim As UInteger i, x, y, b()
Dim As String word, char
Dim As boolean possible

Do
If word = "" Then Exit Do
word = UCase(word)
ReDim b(1 To 20)
possible = TRUE

For i = 1 To Len(word)
char = Mid(word, i, 1)

For x = 1 To 20
If b(x) = 0 Then
If blocks(x, 1) = char Or blocks(x, 2) = char Then
b(x) = 1
Exit For
End If
End If
Next
If x = 21 Then possible = FALSE
Next

Print word, possible
Loop

Data "A", "Bark", "Book", "Treat", "Common", "Squad", "Confuse", ""

' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
A           true
BARK          true
BOOK          false
TREAT         true
COMMON        false
CONFUSE       true

## Gambas

Public Sub Main()
Dim sCheck As String[] = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"]
Dim sBlock As String[] = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]
Dim sList As New String[]
Dim siCount, siLoop As Short
Dim sTemp, sAnswer As String

For Each sTemp In sCheck
sList = sBlock.Copy()
For siCount = 1 To Len(sTemp)
For siLoop = 0 To sList.Max
If InStr(sList[siLoop], Mid(sTemp, siCount, 1)) Then
sList.Extract(siLoop, 1)
sAnswer &= Mid(sTemp, siCount, 1)
Break
Endif
Next
Next

If sAnswer = sTemp Then
Print sTemp & " - True"
Else
Print sTemp & " - False"
End If
Next

End

Output:

A - True
BARK - True
BOOK - False
TREAT - True
COMMON - False
CONFUSE - True

## Go

package main

import (
"fmt"
"strings"
)

func newSpeller(blocks string) func(string) bool {
bl := strings.Fields(blocks)
return func(word string) bool {
return r(word, bl)
}
}

func r(word string, bl []string) bool {
if word == "" {
return true
}
c := word[0] | 32
for i, b := range bl {
if c == b[0]|32 || c == b[1]|32 {
bl[i], bl[0] = bl[0], b
if r(word[1:], bl[1:]) == true {
return true
}
bl[i], bl[0] = bl[0], bl[i]
}
}
return false
}

func main() {
sp := newSpeller(
"BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM")
for _, word := range []string{
"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"} {
fmt.Println(word, sp(word))
}
}
Output:
A true
BARK true
BOOK false
TREAT true
COMMON false
CONFUSE true

## Groovy

Solution:

class ABCSolver {
def blocks

ABCSolver(blocks = []) { this.blocks = blocks }

boolean canMakeWord(rawWord) {
if (rawWord == '' || rawWord == null) { return true; }
def word = rawWord.toUpperCase()
def blocksLeft = [] + blocks
word.every { letter -> blocksLeft.remove(blocksLeft.find { block -> block.contains(letter) }) }
}
}

Test:

def a = new ABCSolver(["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"])

['', 'A', 'BARK', 'book', 'treat', 'COMMON', 'SQuAd', 'CONFUSE'].each {
println "'\${it}': \${a.canMakeWord(it)}"
}
Output:
'': true
'A': true
'BARK': true
'book': false
'treat': true
'COMMON': false
'CONFUSE': true

## Harbour

Harbour Project implements a cross-platform Clipper/xBase compiler.

PROCEDURE Main()

LOCAL cStr

FOR EACH cStr IN { "A", "BARK", "BooK", "TrEaT", "comMON", "sQuAd", "Confuse" }
? PadL( cStr, 10 ), iif( Blockable( cStr ), "can", "cannot" ), "be spelled with blocks."
NEXT

RETURN

STATIC FUNCTION Blockable( cStr )

LOCAL blocks := { ;
"BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", ;
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM" }

LOCAL cFinal := ""
LOCAL i, j

cStr := Upper( cStr )

FOR i := 1 TO Len( cStr )
FOR EACH j IN blocks
IF SubStr( cStr, i, 1 ) \$ j
cFinal += SubStr( cStr, i, 1 )
j := ""
EXIT
ENDIF
NEXT
NEXT

RETURN cFinal == cStr
Output:
A can be spelled with blocks.
BARK can be spelled with blocks.
BooK cannot be spelled with blocks.
TrEaT can be spelled with blocks.
comMON cannot be spelled with blocks.
sQuAd can be spelled with blocks.
Confuse can be spelled with blocks.

The following function returns a list of all the solutions. Since Haskell is lazy, testing whether the list is null will only do the minimal amount of work necessary to determine whether a solution exists.

import Data.List (delete)
import Data.Char (toUpper)

-- returns list of all solutions, each solution being a list of blocks
abc :: (Eq a) => [[a]] -> [a] -> [[[a]]]
abc _ [] = [[]]
abc blocks (c:cs) = [b:ans | b <- blocks, c `elem` b,
ans <- abc (delete b blocks) cs]

blocks = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]

main :: IO ()
main = mapM_ (\w -> print (w, not . null \$ abc blocks (map toUpper w)))
["", "A", "BARK", "BoOK", "TrEAT", "COmMoN", "SQUAD", "conFUsE"]
Output:
("",True)
("A",True)
("BARK",True)
("BoOK",False)
("TrEAT",True)
("COmMoN",False)
("conFUsE",True)

Or, in terms of the bind operator:

import Data.Char (toUpper)
import Data.List (delete)

----------------------- ABC PROBLEM ----------------------

spellWith :: [String] -> String -> [[String]]
spellWith _ [] = [[]]
spellWith blocks (x : xs) = blocks >>= go
where
go b
| x `elem` b = (b :) <\$> spellWith (delete b blocks) xs
| otherwise = []

--------------------------- TEST -------------------------
main :: IO ()
main =
mapM_
( print
. ((,) <*>)
(not . null . spellWith blocks . fmap toUpper)
)
[ "",
"A",
"BARK",
"BoOK",
"TrEAT",
"COmMoN",
"conFUsE"
]

blocks :: [String]
blocks =
words \$
"BO XK DQ CP NA GT RE TG QD FS JW"
<> " HU VI AN OB ER FS LY PC ZM"
Output:
("",True)
("A",True)
("BARK",True)
("BoOK",False)
("TrEAT",True)
("COmMoN",False)
("conFUsE",True)

## Icon and Unicon

Translation of: C

Works in both languages:

procedure main(A)
blocks := ["bo","xk","dq","cp","na","gt","re","tg","qd","fs",
"jw","hu","vi","an","ob","er","fs","ly","pc","zm",&null]
every write("\"",word := !A,"\" ",checkSpell(map(word),blocks)," with blocks.")
end

procedure checkSpell(w,blocks)
blks := copy(blocks)
w ? return if canMakeWord(blks) then "can be spelled"
else "can not be spelled"
end

procedure canMakeWord(blks)
c := move(1) | return
if /blks[1] then fail
every i := 1 to *blks do {
if /blks[i] then (move(-1),fail)
if c == !blks[i] then {
blks[1] :=: blks[i]
if canMakeWord(blks[2:0]) then return
blks[1] :=: blks[i]
}
}
end

Sample run:

->abc "" A BARK BOOK TREAT COMMON SQUAD CONFUSE
"" can be spelled with blocks.
"A" can be spelled with blocks.
"BARK" can be spelled with blocks.
"BOOK" can not be spelled with blocks.
"TREAT" can be spelled with blocks.
"COMMON" can not be spelled with blocks.
"SQUAD" can be spelled with blocks.
"CONFUSE" can be spelled with blocks.
->

## J

Solution:

reduce=: verb define
'rows cols'=. i.&.> \$y
for_c. cols do.
r=. 1 i.~ c {"1 y NB. row idx of first 1 in col
if. r = #rows do. continue. end.
y=. 0 (<((r+1)}.rows);c) } y NB. zero rest of col
y=. 0 (<(r;(c+1)}.cols)) } y NB. zero rest of row
end.
)

abc=: *./@(+./)@[email protected](e."1~ ,)&toupper :: 0:

Examples:

Blocks=:  ];._2 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM '
ExampleWords=: <;._2 'A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE '

Blocks&abc &> ExampleWords
1 1 0 1 0 1 1
require 'format/printf'
'%10s  %s' printf (dquote ; 'FT' {~ Blocks&abc) &> ExampleWords
"A" T
"BaRK" T
"BOoK" F
"tREaT" T
"COmMOn" F
"CoNfuSE" T

Tacit version

delElem=: {~<@<@<
uppc=:(-32*96&<*.123&>)&.(3&u:)
reduc=: ] delElem 1 i.~e."0 1
forms=: (1 - '' -: (reduc L:0/ :: (a:"_)@(<"0@],<@[))&uppc) L:0
Output:
(,.Blocks&forms) ExampleWords
┌───────┬─┐
│A      │1│
├───────┼─┤
│BaRK   │1│
├───────┼─┤
│BOoK   │0│
├───────┼─┤
│tREaT  │1│
├───────┼─┤
│COmMOn │0│
├───────┼─┤
├───────┼─┤
│CoNfuSE│1│
└───────┴─┘

### Alternative Implementation

Another approach might be:

Blocks=:  >;:'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM '
ExampleWords=: ;: 'A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE '

canform=:4 :0
word=: toupper y
need=: #/.~ word,word
relevant=: (x +./@e."1 word) # x
candidates=: word,"1>,{{relevant
+./(((#need){. #/.~)"1 candidates) */ .>:need
)

Example use:

Blocks canform 0{::ExampleWords
1
Blocks canform 1{::ExampleWords
1
Blocks canform 2{::ExampleWords
0
Blocks canform 3{::ExampleWords
1
Blocks canform 4{::ExampleWords
0
Blocks canform 5{::ExampleWords
1
Blocks canform 6{::ExampleWords
1

Explanation:

We only need to consider blocks which contain letters in common with a normalized (upper case) version of the desired word. But we do need to consider all possible combinations of letters from those blocks (see talk page discussion of words like 'ABBA' for more on this issue).

We can classify possibilities by counting how many of each letter occur. If a candidate has at least as many of the required letters as a test case constructed from the word itself, it's a valid candidate.

For example:

Blocks canform 0{::ExampleWords
1
word
A
need
2
relevant
NA
AN
candidates
ANA
ANN
AAA
AAN

Here, the word is simply 'A', and we have two blocks to consider for our word: AN and NA. So we form all possible combinations of the letters of those two bocks, prefix each of them with our word and test whether any of them contain two copies of the letters of our word. (As it happens, three of the candidates are valid, for this trivial example.)

## Java

Translation of: C
Works with: Java version 1.6+
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class ABC {

public static void main(String[] args) {
List<String> blocks = Arrays.asList(
"BO", "XK", "DQ", "CP", "NA",
"GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB",
"ER", "FS", "LY", "PC", "ZM");

for (String word : Arrays.asList("", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE")) {
System.out.printf("%s: %s%n", word.isEmpty() ? "\"\"" : word, canMakeWord(word, blocks));
}
}

public static boolean canMakeWord(String word, List<String> blocks) {
if (word.isEmpty())
return true;

char c = word.charAt(0);
for (int i = 0; i < blocks.size(); i++) {
String b = blocks.get(i);
if (b.charAt(0) != c && b.charAt(1) != c)
continue;
Collections.swap(blocks, 0, i);
if (canMakeWord(word.substring(1), blocks.subList(1, blocks.size())))
return true;
Collections.swap(blocks, 0, i);
}

return false;
}
}
Output:
"": true
A: true
BARK: true
book: false
treat: true
COMMON: false
CONFUSE: true

## JavaScript

### ES5

#### Imperative

The following method uses regular expressions and the string replace function to allow more support for older browsers.

var blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";

function CheckWord(blocks, word) {
// Makes sure that word only contains letters.
if(word !== /([a-z]*)/i.exec(word)[1]) return false;
// Loops through each character to see if a block exists.
for(var i = 0; i < word.length; ++i)
{
// Gets the ith character.
var letter = word.charAt(i);
// Stores the length of the blocks to determine if a block was removed.
var length = blocks.length;
// The regexp gets constructed by eval to allow more browsers to use the function.
var reg = eval("/([a-z]"+letter+"|"+letter+"[a-z])/i");
// This does the same as above, but some browsers do not support...
//var reg = new RegExp("([a-z]"+letter+"|"+letter+"[a-z])", "i");
// Removes all occurrences of the match.
blocks = blocks.replace(reg, "");
// If the length did not change then a block did not exist.
if(blocks.length === length) return false;
}
// If every character has passed then return true.
return true;
};

var words = [
"A",
"BARK",
"BOOK",
"TREAT",
"COMMON",
"CONFUSE"
];

for(var i = 0;i<words.length;++i)
console.log(words[i] + ": " + CheckWord(blocks, words[i]));

Result:

A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
CONFUSE: true

#### Functional

(function (strWords) {

var strBlocks =
'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM',
blocks = strBlocks.split(' ');

function abc(lstBlocks, strWord) {
var lngChars = strWord.length;

if (!lngChars) return [];

var b = lstBlocks[0],
c = strWord[0];

return chain(lstBlocks, function (b) {
return (b.indexOf(c.toUpperCase()) !== -1) ? [
(b + ' ').concat(
abc(removed(b, lstBlocks), strWord.slice(1)))
] : [];
})
}

// Monadic bind (chain) for lists
function chain(xs, f) {
return [].concat.apply([], xs.map(f));
}

// a -> [a] -> [a]
function removed(x, xs) {
var h = xs.length ? xs[0] : null,
t = h ? xs.slice(1) : [];

return h ? (
h === x ? t : [h].concat(removed(x, t))
) : [];
}

function solution(strWord) {
var strAttempt = abc(blocks, strWord)[0].split(',')[0];

// two chars per block plus one space -> 3
return strWord + ((strAttempt.length === strWord.length * 3) ?
' -> ' + strAttempt : ': [no solution]');
}

return strWords.split(' ').map(solution).join('\n');

})('A bark BooK TReAT COMMON squAD conFUSE');
Output:
A -> NA
bark -> BO NA RE XK
BooK: [no solution]
TReAT -> GT RE ER NA TG
COMMON: [no solution]
squAD -> FS DQ HU NA QD
conFUSE -> CP BO NA FS HU FS RE

### ES6

#### Imperative

let characters = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";
let blocks = characters.split(" ").map(pair => pair.split(""));

function isWordPossible(word) {
var letters = [...word.toUpperCase()];
var length = letters.length;
var copy = new Set(blocks);

for (let letter of letters) {
for (let block of copy) {
let index = block.indexOf(letter);

if (index !== -1) {
length--;
copy.delete(block);
break;
}
}

}
return !length;
}

[
"A",
"BARK",
"BOOK",
"TREAT",
"COMMON",
"CONFUSE"
].forEach(word => console.log(`\${word}: \${isWordPossible(word)}`));

Result:

A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
CONFUSE: true

#### Functional

(() => {
"use strict";

// ------------------- ABC BLOCKS --------------------

// spellWith :: [(Char, Char)] -> [Char] -> [[(Char, Char)]]
const spellWith = blocks =>
wordChars => !Boolean(wordChars.length) ? [
[]
] : (() => {
const [x, ...xs] = wordChars;

return blocks.flatMap(
b => b.includes(x) ? (
spellWith(
deleteBy(
p => q => (p[0] === q[0]) && (
p[1] === q[1]
)
)(b)(blocks)
)(xs)
.flatMap(bs => [b, ...bs])
) : []
);
})();

// ---------------------- TEST -----------------------
const main = () => {
const blocks = (
"BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
).split(" ");

return [
"", "A", "BARK", "BoOK", "TrEAT",
]
.map(
x => JSON.stringify([
x, !Boolean(
spellWith(blocks)(
[...x.toLocaleUpperCase()]
)
.length
)
])
)
.join("\n");
};

// ---------------- GENERIC FUNCTIONS ----------------

// deleteBy :: (a -> a -> Bool) -> a -> [a] -> [a]
const deleteBy = fEq =>
x => {
const go = xs => Boolean(xs.length) ? (
fEq(x)(xs[0]) ? (
xs.slice(1)
) : [xs[0], ...go(xs.slice(1))]
) : [];

return go;
};

// MAIN ---
return main();
})();
Output:
["",true]
["A",true]
["BARK",true]
["BoOK",false]
["TrEAT",true]
["COmMoN",false]
["conFUsE",true]

## jq

The problem description seems to imply that if a letter, X, appears on more than one block, its partner will be the same on all blocks. This makes the problem trivial.

# when_index(cond;ary) returns the index of the first element in ary
# that satisfies cond; it uses a helper function that takes advantage
# of tail-recursion optimization in recent versions of jq.
def index_when(cond; ary):
# state variable: counter
def when: if . >= (ary | length) then null
elif ary[.] | cond then .
else (.+1) | when
end;
0 | when;

# Attempt to match a single letter with a block;
# return null if no match, else the remaining blocks
def match_letter(letter):
. as \$ary | index_when( index(letter); \$ary ) as \$ix
| if \$ix == null then null
else del( .[\$ix] )
end;

# Usage: string | abc(blocks)
def abc(blocks):
if length == 0 then true
else
.[0:1] as \$letter
| (blocks | match_letter( \$letter )) as \$blks
| if \$blks == null then false
else .[1:] | abc(\$blks)
end
end;
["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
"JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"] as \$blocks
| "\(.) : \( .|abc(\$blocks) )" ;task
Output:
A : true
BARK : true
BOOK : false
TREAT : true
COMMON : false
CONFUSE : true

## Jsish

Based on Javascript ES5 imperative solution.

#!/usr/bin/env jsish
/* ABC problem, in Jsish. Can word be spelled with the given letter blocks. */
var blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";

function CheckWord(blocks, word) {
var re = /([a-z]*)/i;
if (word !== re.exec(word)[0]) return false;
for (var i = 0; i < word.length; i++) {
var letter = word.charAt(i);
var length = blocks.length;
// trying both sides
var reg = new RegExp("([a-z]"+letter + "|" + letter+"[a-z])", "i");
// remove block once a letter is used
blocks = blocks.replace(reg, "");
if (blocks.length === length) return false;
}
return true;
};

var words = [ "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE" ];

puts("Using blocks:", blocks);
for(var i = 0; i<words.length; i++)
puts(CheckWord(blocks, words[i]) ? "can" : "can't", "spell", words[i]);

/*
=!EXPECTSTART!=
Using blocks: BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
can spell A
can spell BARK
can't spell BOOK
can spell TREAT
can't spell COMMON
can spell CONFUSE
=!EXPECTEND!=
*/
Output:
prompt\$ jsish ABCProblem.jsi
Using blocks: BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
can spell A
can spell BARK
can't spell BOOK
can spell TREAT
can't spell COMMON
can spell CONFUSE

prompt\$ jsish -u ABCProblem.jsi
[PASS] ABCProblem.jsi

## Julia

using Printf

function abc(str::AbstractString, list)
isempty(str) && return true
for i in eachindex(list)
str[end] in list[i] &&
any([abc(str[1:end-1], deleteat!(copy(list), i))]) &&
return true
end
return false
end

let test = ["A", "BARK","BOOK","TREAT","COMMON","SQUAD","CONFUSE"],
list = ["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
"JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]
for str in test
@printf("%-8s |  %s\n", str, abc(str, list))
end
end
Output:
A        |  true
BARK     |  true
BOOK     |  false
TREAT    |  true
COMMON   |  false
CONFUSE  |  true

## Kotlin

Translation of: Java
object ABC_block_checker {
fun run() {
println("\"\": " + blocks.canMakeWord(""))
for (w in words) println("\$w: " + blocks.canMakeWord(w))
}

private fun Array<String>.swap(i: Int, j: Int) {
val tmp = this[i]
this[i] = this[j]
this[j] = tmp
}

private fun Array<String>.canMakeWord(word: String): Boolean {
if (word.isEmpty())
return true

val c = word.first().toUpperCase()
var i = 0
forEach { b ->
if (b.first().toUpperCase() == c || b[1].toUpperCase() == c) {
swap(0, i)
if (drop(1).toTypedArray().canMakeWord(word.substring(1)))
return true
swap(0, i)
}
i++
}

return false
}

private val blocks = arrayOf(
"BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"
)
private val words = arrayOf("A", "BARK", "book", "treat", "COMMON", "SQuAd", "CONFUSE")
}

fun main(args: Array<String>) = ABC_block_checker.run()
Output:
"": true
A: true
BARK: true
book: false
treat: true
COMMON: false
CONFUSE: true

## Liberty BASIC

### Recursive solution

print "Rosetta Code - ABC problem (recursive solution)"
print
blocks\$="BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
data "A"
data "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"
data "XYZZY"

do
if text\$="XYZZY" then exit do
print ">>> can_make_word("; chr\$(34); text\$; chr\$(34); ")"
if canDo(text\$,blocks\$) then print "True" else print "False"
loop while 1
print "Program complete."
end

function canDo(text\$,blocks\$)
'endcase
if len(text\$)=1 then canDo=(instr(blocks\$,text\$)<>0): exit function
'get next letter
ltr\$=left\$(text\$,1)
'cut
if instr(blocks\$,ltr\$)=0 then canDo=0: exit function
'recursion
text\$=mid\$(text\$,2) 'rest
'loop by all word in blocks. Need to make "newBlocks" - all but taken
'optimisation: take only fitting blocks
wrd\$="*"
i=0
while wrd\$<>""
i=i+1
wrd\$=word\$(blocks\$, i)
if instr(wrd\$, ltr\$) then
'newblocks without wrd\$
pos=instr(blocks\$,wrd\$)
newblocks\$=left\$(blocks\$, pos-1)+mid\$(blocks\$, pos+3)
canDo=canDo(text\$,newblocks\$)
'first found cuts
if canDo then exit while
end if
wend
end function

Output:
Rosetta Code - ABC problem (recursive solution)

>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True
Program complete.

### Procedural solution

print "Rosetta Code - ABC problem (procedural solution)"
print
w\$(1)="A"
w\$(2)="BARK"
w\$(3)="BOOK"
w\$(4)="TREAT"
w\$(5)="COMMON"
w\$(7)="CONFUSE"

for x=1 to 7
print ">>> can_make_word("; chr\$(34); w\$(x); chr\$(34); ")"
if CanMakeWord(w\$(x)) then print "True" else print "False"
next x
print "Program complete."
end

function CanMakeWord(x\$)
global DoneWithWord, BlocksUsed, LetterOK, Possibility
dim block\$(20,2), block(20,2)
'numeric blocks, col 0 flags used block
block(1,1)=asc("B")-64: block(1,2)=asc("O")-64
block(2,1)=asc("X")-64: block(2,2)=asc("K")-64
block(3,1)=asc("D")-64: block(3,2)=asc("Q")-64
block(4,1)=asc("C")-64: block(4,2)=asc("P")-64
block(5,1)=asc("N")-64: block(5,2)=asc("A")-64
block(6,1)=asc("G")-64: block(6,2)=asc("T")-64
block(7,1)=asc("R")-64: block(7,2)=asc("E")-64
block(8,1)=asc("T")-64: block(8,2)=asc("G")-64
block(9,1)=asc("Q")-64: block(9,2)=asc("D")-64
block(10,1)=asc("F")-64: block(10,2)=asc("S")-64
block(11,1)=asc("J")-64: block(11,2)=asc("W")-64
block(12,1)=asc("H")-64: block(12,2)=asc("U")-64
block(13,1)=asc("V")-64: block(13,2)=asc("I")-64
block(14,1)=asc("A")-64: block(14,2)=asc("N")-64
block(15,1)=asc("O")-64: block(15,2)=asc("B")-64
block(16,1)=asc("E")-64: block(16,2)=asc("R")-64
block(17,1)=asc("F")-64: block(17,2)=asc("S")-64
block(18,1)=asc("L")-64: block(18,2)=asc("Y")-64
block(19,1)=asc("P")-64: block(19,2)=asc("C")-64
block(20,1)=asc("Z")-64: block(20,2)=asc("M")-64

x\$=upper\$(x\$)
for x=1 to len(x\$)
y\$=mid\$(x\$,x,1)
if y\$>="A" and y\$<="Z" then w\$=w\$+y\$
next x
if w\$="" then exit function
DoneWithWord=0: BlocksUsed=0
l=len(w\$)
dim LetterOK(l)
dim alphabet(26,1) 'clear letter-usage array
for x=1 to 20 'load block letters into letter-usage array col 0
alphabet(block(x,1),0)+=1
alphabet(block(x,2),0)+=1
next x
for x=1 to l 'load current word into letter-usage aray col 1
wl\$=mid\$(w\$,x,1): w=asc(wl\$)-64
alphabet(w,1)+=1
next x

for x=1 to 26 ' test for more of any letter in the word than in the blocks
if alphabet(x,1)>alphabet(x,0) then exit function
next x

[NextLetter]
if wl<l then wl=wl+1 else goto [DoneWithWord]
wl\$=mid\$(w\$,wl,1): w=asc(wl\$)-64
LetterOK=0
' if there's only one of the letter in the blocks then you must use that block
if alphabet(w,0)=1 then
call OnlyBlock w
LetterOK(wl)=1
if DoneWithWord then goto [DoneWithWord] else goto [NextLetter]
end if
' if more than one of the letter in the blocks, then try to use one that has
' an unused letter on other side (a "Free Block")
call FindFreeBlock w
if LetterOK then LetterOK(wl)=1
goto [NextLetter]

[DoneWithWord]
if BlocksUsed=l then CanMakeWord=1: exit function
if DoneWithWord then exit function
for x=1 to l
if not(LetterOK(x)) then
NumericLetter=asc(mid\$(w\$,x,1))-64
LetterOK=0
call OnlyBlock NumericLetter
if LetterOK then LetterOK(x)=1 else exit for
end if
next x
goto [DoneWithWord]
end function

sub OnlyBlock NumericLetter
for x=1 to 20
if (block(x, 1)=NumericLetter or block(x, 2)=NumericLetter) _
and block(x, 0)=0 then
call UseBlock x, NumericLetter
exit sub
end if
next x
DoneWithWord=1
end sub

sub FindFreeBlock NumericLetter
Possibility=0
for x=1 to 20
if block(x, 0)=0 then 'block not used
if block(x,1)=NumericLetter then
if alphabet(block(x,2),1)=0 then
call UseBlock x, NumericLetter
exit sub
end if
Possibility=Possibility+1
end if
if block(x,2)=NumericLetter then
if alphabet(block(x,1),1)=0 then
call UseBlock x, NumericLetter
exit sub
end if
Possibility=Possibility+1
end if
end if
next x
end sub

sub UseBlock BlockNumber, NumericLetter
block(BlockNumber, 0)=1 'Mark block as used
BlocksUsed=BlocksUsed+1
LetterOK=1
end sub

Output:
Rosetta Code - ABC problem (procedural solution)

>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True
Program complete.

## Logo

make "blocks [[B O] [X K] [D Q] [C P] [N A] [G T] [R E] [T G] [Q D] [F S]
[J W] [H U] [V I] [A N] [O B] [E R] [F S] [L Y] [P C] [Z M]]

to can_make? :word [:avail :blocks]
if empty? :word [output "true]
local "letter make "letter first :word
foreach :avail [
local "i make "i #
local "block make "block ?
if member? :letter :block [
if (can_make? bf :word filter [notequal? # :i] :avail) [output "true]
]
]
output "false
end

foreach [A BARK BOOK TREAT COMMON SQUAD CONFUSE] [
print sentence word ? ": can_make? ?
]

bye
Output:
A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
CONFUSE: true

## Lua

blocks = {
{"B","O"}; {"X","K"}; {"D","Q"}; {"C","P"};
{"N","A"}; {"G","T"}; {"R","E"}; {"T","G"};
{"Q","D"}; {"F","S"}; {"J","W"}; {"H","U"};
{"V","I"}; {"A","N"}; {"O","B"}; {"E","R"};
{"F","S"}; {"L","Y"}; {"P","C"}; {"Z","M"};
};

function canUse(table, letter)
for i,v in pairs(blocks) do
if (v[1] == letter:upper() or v[2] == letter:upper()) and table[i] then
table[i] = false;
return true;
end
end
return false;
end

function canMake(Word)
local Taken = {};
for i,v in pairs(blocks) do
table.insert(Taken,true);
end
local found = true;
for i = 1,#Word do
if not canUse(Taken,Word:sub(i,i)) then
found = false;
end
end
print(found)
end
Output:
canMake("A"): true
canMake("BARK"): true
canMake("BOOK"): false
canMake("TREAT"): true
canMake("COMMON"): false
canMake("CONFUSE"): true

## M2000 Interpreter

We use a subroutine inside a module. Subs are in the same namespace as the module which call them. Subs may exist in the end of module, or in the parent module (which module defined). We have to use Local to define new variables which shadow any module variable. When a sub exit all new variables which made there erased. Modules run on objects which "interprets" code, and subs use modules objects, so they are lighter than modules. A module hold a separate return stack for subs, gosub and for next structures ( a for {} use process stack, and is twice faster as the simple For Next). This return stack is a stack object, which is a collection of objects in heap, so we can use Recursion.Limit 100000 to set limit to 100000 calls for subs. Here we use a for next and a subroutine, using modules dedicated return stack. We can call can_make_word() using name or using Gosub. Gosub can call subs as labels, and expect Return to return from sub. These routines are more lighter than subs, because they run as code is in module, and any new variable stay until module exit. So we never make local variables or if we want locals we have to use Fopr This { }, the block for temporary definitions.

Module ABC {
can_make_word("A")
can_make_word("BaRk")
can_make_word("BOOK")
can_make_word("TREAT")
can_make_word("CommoN")
Gosub can_make_word("CONFUSE") ' we can use Gosub before
Sub can_make_word(c\$)
local b\$=ucase\$(c\$)
local i, a\$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM", m
for i=1 to len(b\$)
m=Instr(a\$,mid\$(b\$, i, 1))
If m=0 Then Exit for
Insert binary.or(m-1, 1),2 a\$="" ' delete 2 chars
Next i
Print c\$, m<>0
End Sub
}
ABC

Output:
A          True
BaRk       True
BOOK      False
TREAT      True
CommoN    False
CONFUSE    True

## Maple

canSpell := proc(w)
local blocks, i, j, word, letterFound;
blocks := Array([["B", "O"], ["X", "K"], ["D", "Q"], ["C", "P"], ["N", "A"], ["G", "T"], ["R", "E"], ["T", "G"],
["Q", "D"], ["F", "S"], ["J", "W"], ["H", "U"], ["V", "I"], ["A", "N"], ["O", "B"], ["E", "R"],
["F", "S"], ["L", "Y"], ["P", "C"], ["Z", "M"]]);
word := StringTools[UpperCase](convert(w, string));
for i to length(word) do
letterFound := false;
for j to numelems(blocks)/2 do
if not letterFound and (substring(word, i) = blocks[j,1] or substring(word, i) = blocks[j,2]) then
blocks[j,1] := undefined;
blocks[j,2] := undefined;
letterFound := true;
end if;
end do;
if not letterFound then
return false;
end if;
end do;
return true;
end proc:

seq(printf("%a: %a\n", i, canSpell(i)), i in [a, Bark, bOok, treat, COMMON, squad, confuse]);
Output:
a: true
Bark: true
bOok: false
treat: true
COMMON: false
confuse: true

## Mathematica / Wolfram Language

blocks=Partition[Characters[ToLowerCase["BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"]],2];
ClearAll[DoStep,ABCBlockQ]
DoStep[chars_List,blcks_List,chosen_List]:=Module[{opts},
If[chars=!={},
opts=Select[blcks,MemberQ[#,First[chars]]&];
{Rest[chars],DeleteCases[blcks,#,1,1],Append[chosen,#]}&/@opts
,
{{chars,blcks,chosen}}
]
]
DoStep[opts_List]:=Flatten[[email protected]@@opts,1]
ABCBlockQ[str_String]:=(FixedPoint[DoStep,{{Characters[ToLowerCase[str]],blocks,{}}}]=!={})

Output:
ABCBlockQ["A"]
ABCBlockQ["BARK"]
ABCBlockQ["BOOK"]
ABCBlockQ["TREAT"]
ABCBlockQ["COMMON"]
ABCBlockQ["CONFUSE"]
True
True
False
True
False
True
True

## MATLAB / Octave

function testABC
combos = ['BO' ; 'XK' ; 'DQ' ; 'CP' ; 'NA' ; 'GT' ; 'RE' ; 'TG' ; 'QD' ; ...
'FS' ; 'JW' ; 'HU' ; 'VI' ; 'AN' ; 'OB' ; 'ER' ; 'FS' ; 'LY' ; ...
'PC' ; 'ZM'];
words = {'A' 'BARK' 'BOOK' 'TREAT' 'COMMON' 'SQUAD' 'CONFUSE'};
for k = 1:length(words)
possible = canMakeWord(words{k}, combos);
fprintf('Can%s make word %s.\n', char(~possible.*'NOT'), words{k})
end
end

function isPossible = canMakeWord(word, combos)
word = lower(word);
combos = lower(combos);
isPossible = true;
k = 1;
while isPossible && k <= length(word)
[r, c] = find(combos == word(k), 1);
if ~isempty(r)
combos(r, :) = '';
else
isPossible = false;
end
k = k+1;
end
end
Output:
Can make word A.
Can make word BARK.
CanNOT make word BOOK.
Can make word TREAT.
CanNOT make word COMMON.
Can make word SQUAD.
Can make word CONFUSE.

## MAXScript

### Recursive

Recursively checks if the word is possible if a block is removed from the array.

-- This is the blocks array
global GlobalBlocks = #("BO","XK","DQ","CP","NA", \
"GT","RE","TG","QD","FS", \
"JW","HU","VI","AN","OB", \
"ER","FS","LY","PC","ZM")

-- This function returns true if "_str" is part of "_word", false otherwise
fn occurs _str _word =
(
if _str != undefined and _word != undefined then
(
matchpattern _word pattern:("*"+_str+"*")
) else return false
)

-- This is the main function
fn isWordPossible word blocks: = -- blocks is a keyword argument
(
word = toupper word -- convert the string to upper case, to make it case insensitive
if blocks == unsupplied do blocks = GlobalBlocks
-- if blocks (keyword argument) is unsupplied, use the global blocks array (this is for recursion)

blocks = deepcopy blocks

local pos = 1 -- start at the beginning of the word
local solvedLetters = #() -- this array stores the indices of solved letters

while pos <= word.count do -- loop through every character in the word
(
local possibleBlocks = #() -- this array stores the blocks which can be used to make that letter
for b = 1 to Blocks.count do -- this loop finds all the possible blocks that can be used to make that letter
(
if occurs word[pos] blocks[b] do
(
appendifunique possibleBlocks b
)
)
if possibleBlocks.count > 0 then -- if it found any blocks
(
if possibleBlocks.count == 1 then -- if it found one block, then continue
(
appendifunique solvedLetters pos
deleteitem blocks possibleblocks[1]
pos += 1
)
else -- if it found more than one
(
for b = 1 to possibleBlocks.count do -- loop through every possible block
(
local possibleBlock = blocks[possibleBlocks[b]]
local blockFirstLetter = possibleBlock[1]
local blockSecondLetter = possibleBlock[2]
local matchingLetter = if blockFirstLetter == word[pos] then 1 else 2
-- ^ this is the index of the matching letter on the block

local notMatchingIndex = if matchingLetter == 1 then 2 else 1
local notMatchingLetter = possibleBlock[notMatchingIndex]
-- ^ this is the other letter on the block

if occurs notMatchingLetter (substring word (pos+1) -1) then
( -- if the other letter occurs in the rest of the word
local removedBlocks = deepcopy blocks -- copy the current blocks array
deleteitem removedBlocks possibleBlocks[b] -- remove the item from the copied array

-- recursively check if the word is possible if that block is taken away from the array:
if (isWordPossible (substring word (pos+1) -1) blocks:removedBlocks) then
( -- if it is, then remove the block and move to next character
appendifunique solvedLetters pos
deleteitem blocks possibleblocks[1]
pos += 1
exit
)
else
( -- if it isn't and it looped through every possible block, then the word is not possible
if b == possibleBlocks.count do return false
)
)
else
( -- if the other letter on this block doesn't occur in the rest of the word, then the letter is solved, continue
appendifunique solvedLetters pos
deleteitem blocks possibleblocks[b]
pos += 1
exit
)
)
)
) else return false -- if it didn't find any blocks, then return false
)

makeuniquearray solvedLetters -- make sure there are no duplicates in the solved array
if solvedLetters.count != word.count then return false -- if number of solved letters is not equal to word length
else
( -- this checks if all the solved letters are the same as the word
check = ""
for bit in solvedLetters do append check word[bit]
if check == word then return true else return false
)
)

Output:

iswordpossible "a"
true
iswordpossible "bark"
true
iswordpossible "book"
false
iswordpossible "treat"
true
iswordpossible "common"
false
true
iswordpossible "confuse"
true

### Non-recursive

fn isWordPossible2 word =
(
Blocks = #("BO","XK","DQ","CP","NA", \
"GT","RE","TG","QD","FS", \
"JW","HU","VI","AN","OB", \
"ER","FS","LY","PC","ZM")
word = toupper word
local pos = 1
local solvedLetters = #()
while pos <= word.count do
(
for i = 1 to blocks.count do
(
if (matchpattern blocks[i] pattern:("*"+word[pos]+"*")) then
(
deleteitem blocks i
appendifunique solvedLetters pos
pos +=1
exit
)
else if i == blocks.count do return false
)
)
if solvedLetters.count == word.count then
(
local check = ""
for bit in solvedLetters do append check word[bit]
if check == word then return true else return false
) else return false
)

Both versions are good for this example, but the non-recursive version won't work if the blocks are more random, because it just takes the first found block, and the recursive version decides which one to use. For example, if blocks are: #("RT","WA","WO","TB","RE") Then:

iswordpossible "water"
true
iswordpossible2 "water"
false

Non-recursive version quickly decides that it's not possible, even though it clearly is.

## Mercury

:- module abc.
:- interface.
:- import_module io.
:- pred main(io::di, io::uo) is det.
:- implementation.
:- import_module list, string, char.

:- type block == {char, char}.

:- pred take(char, list(block), list(block)).
:- mode take(in, in, out) is nondet.
take(C, !Blocks) :-
list.delete(!.Blocks, {A, B}, !:Blocks),
( A = C ; B = C ).

:- pred can_make_word(list(char)::in, list(block)::in) is semidet.
can_make_word([], _).
can_make_word([C|Cs], !.Blocks) :-
take(C, !Blocks),
can_make_word(Cs, !.Blocks).

main(!IO) :-
Blocks = [
{'B', 'O'}, {'X', 'K'}, {'D', 'Q'}, {'C', 'P'}, {'N', 'A'},
{'G', 'T'}, {'R', 'E'}, {'T', 'G'}, {'Q', 'D'}, {'F', 'S'},
{'J', 'W'}, {'H', 'U'}, {'V', 'I'}, {'A', 'N'}, {'O', 'B'},
{'E', 'R'}, {'F', 'S'}, {'L', 'Y'}, {'P', 'C'}, {'Z', 'M'}
],
Words = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"],
foldl((pred(W::in, !.IO::di, !:IO::uo) is det :-
P = can_make_word(to_char_list(W), Blocks),
io.format("can_make_word(""%s"") :- %s.\n",
[s(W), s(if P then "true" else "fail")], !IO)),
Words, !IO).

Note that 'P', in the foldl near the end, is not a boolean variable, but a zero-arity currying of can_make_word (i.e., it's a 'lambda' that takes no arguments and then calls can_make_word with all of the already-supplied arguments).

## MiniScript

allBlocks = ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"]

swap = function(list, index1, index2)
tmp = list[index1]
list[index1] = list[index2]
list[index2] = tmp
end function

canMakeWord = function(str, blocks)
if str == "" then return true
c = str[0].upper
for i in range(0, blocks.len - 1)
bl = blocks[i]
if c != bl[0] and c != bl[1] then continue
swap blocks, 0, i
if canMakeWord(str[1:], blocks[1:]) then return true
swap blocks, 0, i
end for
return false
end function

for val in ["", "A", "BARK", "book", "Treat", "COMMON", "sQuAD", "CONFUSE"]
out = """"""
if val.len != 0 then out = val
print out + ": " + canMakeWord(val, allBlocks)
end for

## Nim

Works with: Nim version 0.20.0
import std / strutils

func canMakeWord(blocks: seq[string]; word: string): bool =
if blocks.len < word.len: return false
if word.len == 0: return true

let ch = word[0].toUpperAscii
for i, pair in blocks:
if ch in pair and
(blocks[0..<i] & blocks[i+1..^1]).canMakeWord(word[1..^1]):
return true

proc main =
for (blocks, words) in [
("BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM".splitWhitespace,
@["A", "bArK", "BOOK", "treat", "common", "sQuAd", "CONFUSE"]),
("AB AB AC AC".splitWhitespace, @["ABBa"]),
("US TZ AO QA".splitWhitespace, @["Auto"])
]:
echo "Using the blocks ", blocks.join(" ")
for word in words:
echo " can we make the word '\$#'? \$#" % [
word, if blocks.canMakeWord(word): "yes" else: "no"]
echo()

when isMainModule: main()
Output:
Using the blocks BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
can we make the word 'A'? yes
can we make the word 'bArK'? yes
can we make the word 'BOOK'? no
can we make the word 'treat'? yes
can we make the word 'common'? no
can we make the word 'sQuAd'? yes
can we make the word 'CONFUSE'? yes

Using the blocks AB AB AC AC
can we make the word 'ABBa'? yes

Using the blocks US TZ AO QA
can we make the word 'Auto'? yes

## Oberon-2

Works with oo2c Version 2

MODULE ABCBlocks;
IMPORT
Object,
Out;

VAR
blocks: ARRAY 20 OF STRING;

PROCEDURE CanMakeWord(w: STRING): BOOLEAN;
VAR
used: ARRAY 20 OF LONGINT;
wChars: Object.CharsLatin1;
i,j: LONGINT;

PROCEDURE IsUsed(i: LONGINT): BOOLEAN;
VAR
b: LONGINT;
BEGIN
b := 0;
WHILE (b < LEN(used) - 1) & (used[b] # -1) DO
IF used[b] = i THEN RETURN TRUE END;
INC(b)
END;
RETURN FALSE
END IsUsed;

PROCEDURE GetBlockFor(blocks: ARRAY OF STRING; c: CHAR): LONGINT;
VAR
i: LONGINT;
BEGIN
i := 0;
WHILE (i < LEN(blocks)) DO
IF (blocks[i].IndexOf(c,0) >= 0) & (~IsUsed(i)) THEN RETURN i END;
INC(i)
END;

RETURN -1;
END GetBlockFor;

BEGIN
FOR i := 0 TO LEN(used) - 1 DO used[i] := -1 END;
wChars := w(Object.String8).CharsLatin1();

i := 0;
WHILE (i < LEN(wChars^) - 1) DO
j := GetBlockFor(blocks,CAP(wChars[i]));
IF j < 0 THEN RETURN FALSE END;
used[i] := j;
INC(i)
END;
RETURN TRUE
END CanMakeWord;

BEGIN
blocks[0] := "BO";
blocks[1] := "XK";
blocks[2] := "DQ";
blocks[3] := "CP";
blocks[4] := "NA";
blocks[5] := "GT";
blocks[6] := "RE";
blocks[7] := "TG";
blocks[8] := "QD";
blocks[9] := "FS";
blocks[10] := "JW";
blocks[11] := "HU";
blocks[12] := "VI";
blocks[13] := "AN";
blocks[14] := "OB";
blocks[15] := "ER";
blocks[16] := "FS";
blocks[17] := "LY";
blocks[18] := "PC";
blocks[19] := "ZM";

Out.String("A: ");Out.Bool(CanMakeWord("A"));Out.Ln;
Out.String("BARK: ");Out.Bool(CanMakeWord("BARK"));Out.Ln;
Out.String("BOOK: ");Out.Bool(CanMakeWord("BOOK"));Out.Ln;
Out.String("TREAT: ");Out.Bool(CanMakeWord("TREAT"));Out.Ln;
Out.String("COMMON: ");Out.Bool(CanMakeWord("COMMON"));Out.Ln;
Out.String("confuse: ");Out.Bool(CanMakeWord("confuse"));Out.Ln;
END ABCBlocks.

Output:

A: TRUE
BARK: TRUE
BOOK: FALSE
TREAT: TRUE
COMMON: FALSE
confuse: TRUE

## Objeck

Translation of: Java
class Abc {
function : Main(args : String[]) ~ Nil {
blocks := ["BO", "XK", "DQ", "CP", "NA",
"GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB",
"ER", "FS", "LY", "PC", "ZM"];

IO.Console->Print("\"\": ")->PrintLine(CanMakeWord("", blocks));
IO.Console->Print("A: ")->PrintLine(CanMakeWord("A", blocks));
IO.Console->Print("BARK: ")->PrintLine(CanMakeWord("BARK", blocks));
IO.Console->Print("book: ")->PrintLine(CanMakeWord("book", blocks));
IO.Console->Print("treat: ")->PrintLine(CanMakeWord("treat", blocks));
IO.Console->Print("COMMON: ")->PrintLine(CanMakeWord("COMMON", blocks));
IO.Console->Print("CONFUSE: ")->PrintLine(CanMakeWord("CONFUSE", blocks));
}

function : CanMakeWord(word : String, blocks : String[]) ~ Bool {
if(word->Size() = 0) {
return true;
};

c := word->Get(0)->ToUpper();
for(i := 0; i < blocks->Size(); i++;) {
b := blocks[i];
if(<>(b->Get(0)->ToUpper() <> c & b->Get(1)->ToUpper() <> c)) {
Swap(0, i, blocks);
new_word := word->SubString(1, word->Size() - 1);
new_blocks := String->New[blocks->Size() - 1];
Runtime->Copy(new_blocks, 0, blocks, 1, blocks->Size() - 1);
if(CanMakeWord(new_word, new_blocks)) {
return true;
};
Swap(0, i, blocks);
};
};

return false;
}

function : native : Swap(i : Int, j : Int, arr : String[]) ~ Nil {
tmp := arr[i];
arr[i] := arr[j];
arr[j] := tmp;
}
}
"": true
A: true
BARK: true
book: false
treat: true
COMMON: false
CONFUSE: true

## OCaml

let blocks = [
('B', 'O'); ('X', 'K'); ('D', 'Q'); ('C', 'P');
('N', 'A'); ('G', 'T'); ('R', 'E'); ('T', 'G');
('Q', 'D'); ('F', 'S'); ('J', 'W'); ('H', 'U');
('V', 'I'); ('A', 'N'); ('O', 'B'); ('E', 'R');
('F', 'S'); ('L', 'Y'); ('P', 'C'); ('Z', 'M');
]

let find_letter blocks c =
let found, remaining =
List.partition (fun (c1, c2) -> c1 = c || c2 = c) blocks
in
match found with
| _ :: res -> Some (res @ remaining)
| _ -> None

let can_make_word w =
let n = String.length w in
let rec aux i _blocks =
if i >= n then true else
match find_letter _blocks w.[i] with
| None -> false
| Some rem_blocks ->
aux (succ i) rem_blocks
in
aux 0 blocks

let test label f (word, should) =
Printf.printf "- %s %S = %B (should: %B)\n" label word (f word) should

let () =
List.iter (test "can make word" can_make_word) [
"A", true;
"BARK", true;
"BOOK", false;
"TREAT", true;
"COMMON", false;
"CONFUSE", true;
]
Output:
\$ ocaml canmakeword.ml
- can make word "A" = true  (should: true)
- can make word "BARK" = true  (should: true)
- can make word "BOOK" = false  (should: false)
- can make word "TREAT" = true  (should: true)
- can make word "COMMON" = false  (should: false)
- can make word "SQUAD" = true  (should: true)
- can make word "CONFUSE" = true  (should: true)

## Oforth

import: mapping

["BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS","JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"]
const: ABCBlocks

: canMakeWord(w, blocks)
| i |
w empty? ifTrue: [ true return ]
blocks size loop: i [
w first >upper blocks at(i) include? ifFalse: [ continue ]
canMakeWord( w right( w size 1- ), blocks del(i, i) ) ifTrue: [ true return ]
]
false
;
Output:
["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"] map(#[ ABCBlocks canMakeWord]) .
[1, 1, 0, 1, 0, 1, 1]

## OpenEdge/Progress

FUNCTION canMakeWord RETURNS LOGICAL (INPUT pWord AS CHARACTER) FORWARD.

/* List of blocks */
DEFINE TEMP-TABLE ttBlocks NO-UNDO
FIELD ttFaces AS CHARACTER FORMAT "x(1)" EXTENT 2
FIELD ttUsed AS LOGICAL.

/* Fill in list of blocks */

DEFINE VARIABLE chWords AS CHARACTER EXTENT 7 NO-UNDO.
ASSIGN chWords[1] = "A"
chWords[2] = "BARK"
chWords[3] = "BOOK"
chWords[4] = "TREAT"
chWords[5] = "COMMON"
chWords[7] = "CONFUSE".

DEFINE FRAME frmResult
WITH NO-LABELS 7 DOWN USE-TEXT.

DEFINE VARIABLE i AS INTEGER NO-UNDO.
DO i = 1 TO 7:
DISPLAY chWords[i] + " = " + STRING(canMakeWord(chWords[i])) FORMAT "x(25)" WITH FRAME frmResult.
DOWN WITH FRAME frmResult.
END.

DEFINE INPUT PARAMETER i-chBlockvalue AS CHARACTER NO-UNDO.

IF (LENGTH(i-chBlockValue) <> 2)
THEN RETURN ERROR.

CREATE ttBlocks.
ASSIGN ttBlocks.ttFaces[1] = SUBSTRING(i-chBlockValue, 1, 1)
ttBlocks.ttFaces[2] = SUBSTRING(i-chBlockValue, 2, 1).
END PROCEDURE.

FUNCTION blockInList RETURNS LOGICAL (pChar AS CHARACTER):
/* Find first unused block in list */
FIND FIRST ttBlocks WHERE (ttBlocks.ttFaces[1] = pChar
OR ttBlocks.ttFaces[2] = pChar)
AND NOT ttBlocks.ttUsed NO-ERROR.
IF (AVAILABLE ttBlocks) THEN DO:
/* found it! set to used and return true */
ASSIGN ttBlocks.ttUsed = TRUE.
RETURN TRUE.
END.
ELSE RETURN FALSE.
END FUNCTION.

FUNCTION canMakeWord RETURNS LOGICAL (INPUT pWord AS CHARACTER):
DEFINE VARIABLE i AS INTEGER NO-UNDO.
DEFINE VARIABLE chChar AS CHARACTER NO-UNDO.

/* Word has to be valid */
IF (LENGTH(pWord) = 0)
THEN RETURN FALSE.

DO i = 1 TO LENGTH(pWord):
/* get the char */
chChar = SUBSTRING(pWord, i, 1).

/* Check to see if this is a letter? */
IF ((ASC(chChar) < 65) OR (ASC(chChar) > 90) AND
(ASC(chChar) < 97) OR (ASC(chChar) > 122))
THEN RETURN FALSE.

/* Is block is list (and unused) */
IF NOT blockInList(chChar)
THEN RETURN FALSE.
END.

/* Reset all blocks */
FOR EACH ttBlocks:
ASSIGN ttUsed = FALSE.
END.
RETURN TRUE.
END FUNCTION.

Output:
A = yes
BARK = yes
BOOK = no
TREAT = yes
COMMON = no
CONFUSE = yes

## Order

#include <order/interpreter.h>
#include <order/lib.h>

// Because of technical limitations, characters within a "string" must be separated by white spaces.
// For the sake of simplicity, only upper-case characters are supported here.

// A few lines of boiler-plate oriented programming are needed to enable character parsing and comparison.
#define ORDER_PP_TOKEN_A (A)
#define ORDER_PP_TOKEN_B (B)
#define ORDER_PP_TOKEN_C (C)
#define ORDER_PP_TOKEN_D (D)
#define ORDER_PP_TOKEN_E (E)
#define ORDER_PP_TOKEN_F (F)
#define ORDER_PP_TOKEN_G (G)
#define ORDER_PP_TOKEN_H (H)
#define ORDER_PP_TOKEN_I (I)
#define ORDER_PP_TOKEN_J (J)
#define ORDER_PP_TOKEN_K (K)
#define ORDER_PP_TOKEN_L (L)
#define ORDER_PP_TOKEN_M (M)
#define ORDER_PP_TOKEN_N (N)
#define ORDER_PP_TOKEN_O (O)
#define ORDER_PP_TOKEN_P (P)
#define ORDER_PP_TOKEN_Q (Q)
#define ORDER_PP_TOKEN_R (R)
#define ORDER_PP_TOKEN_S (S)
#define ORDER_PP_TOKEN_T (T)
#define ORDER_PP_TOKEN_U (U)
#define ORDER_PP_TOKEN_V (V)
#define ORDER_PP_TOKEN_W (W)
#define ORDER_PP_TOKEN_X (X)
#define ORDER_PP_TOKEN_Y (Y)
#define ORDER_PP_TOKEN_Z (Z)

#define ORDER_PP_SYM_A(...) __VA_ARGS__
#define ORDER_PP_SYM_B(...) __VA_ARGS__
#define ORDER_PP_SYM_C(...) __VA_ARGS__
#define ORDER_PP_SYM_D(...) __VA_ARGS__
#define ORDER_PP_SYM_E(...) __VA_ARGS__
#define ORDER_PP_SYM_F(...) __VA_ARGS__
#define ORDER_PP_SYM_G(...) __VA_ARGS__
#define ORDER_PP_SYM_H(...) __VA_ARGS__
#define ORDER_PP_SYM_I(...) __VA_ARGS__
#define ORDER_PP_SYM_J(...) __VA_ARGS__
#define ORDER_PP_SYM_K(...) __VA_ARGS__
#define ORDER_PP_SYM_L(...) __VA_ARGS__
#define ORDER_PP_SYM_M(...) __VA_ARGS__
#define ORDER_PP_SYM_N(...) __VA_ARGS__
#define ORDER_PP_SYM_O(...) __VA_ARGS__
#define ORDER_PP_SYM_P(...) __VA_ARGS__
#define ORDER_PP_SYM_Q(...) __VA_ARGS__
#define ORDER_PP_SYM_R(...) __VA_ARGS__
#define ORDER_PP_SYM_S(...) __VA_ARGS__
#define ORDER_PP_SYM_T(...) __VA_ARGS__
#define ORDER_PP_SYM_U(...) __VA_ARGS__
#define ORDER_PP_SYM_V(...) __VA_ARGS__
#define ORDER_PP_SYM_W(...) __VA_ARGS__
#define ORDER_PP_SYM_X(...) __VA_ARGS__
#define ORDER_PP_SYM_Y(...) __VA_ARGS__
#define ORDER_PP_SYM_Z(...) __VA_ARGS__

/// 8blocks_lexer (string) : Seq String -> Seq (Seq Sym)
#define ORDER_PP_DEF_8blocks_lexer ORDER_PP_FN \
(8fn (8S \
,8seq_map (8tokens_to_seq \
,8S \
) \
) \
)

// Keying the blocks makes filtering them way more efficient than by comparing their letters.
/// 8seq_keyed (sequence) : Seq a -> Seq (Pair Num a)
#define ORDER_PP_DEF_8seq_keyed ORDER_PP_FN \
(8fn (8S \
,8stream_to_seq (8stream_pair_with (8pair \
,8stream_of_naturals \
,8seq_to_stream (8S) \
) \
) \
) \
)

/// 8abc_internal (blocks, word) : Seq (Pair Num (Seq Token)) -> Seq Token -> Bool
#define ORDER_PP_DEF_8abc_internal ORDER_PP_FN \
(8fn (8B, 8W \
,8if (8seq_is_nil (8W) \
,8true \
,8lets ((8C, 8seq_head (8W)) \
(8S, 8seq_filter (8chain (8seq_exists (8same (8C)) \
,8tuple_at_1 \
) \
,8B \
) \
) \
(8T, 8seq_map (8chain (8flip (8seq_filter \
,8B \
) \
,8bin_pr (8not_eq \
,8tuple_at_0 \
) \
) \
,8S \
) \
) \
,8seq_exists (8flip (8abc_internal \
,8seq_tail (8W) \
) \
,8T \
) \
) \
) \
) \
)

/// 8abc (blocks, word) : Seq (String) -> String -> Bool
#define ORDER_PP_DEF_8abc ORDER_PP_FN \
(8fn (8B, 8W \
,8abc_internal (8seq_keyed (8blocks_lexer (8B)) \
,8tokens_to_seq (8W) \
) \
) \
)

#define ORDER_PP_DEF_8blocks ORDER_PP_CONST ( \
(B O) \
(X K) \
(D Q) \
(C P) \
(N A) \
(G T) \
(R E) \
(T G) \
(Q D) \
(F S) \
(J W) \
(H U) \
(V I) \
(A N) \
(O B) \
(E R) \
(F S) \
(L Y) \
(P C) \
(Z M) \
)

ORDER_PP
(8seq_map (8step (8pair (8identity
,8abc (8blocks)
)
)
,8quote ((A)
(B A R K)
(B O O K)
(T R E A T)
(C O M M O N)
(S Q U A D)
(C O N F U S E)
)
)
)

Output:
((A,8true))((B A R K,8true))((B O O K,8false))((T R E A T,8true))((C O M M O N,8false))((S Q U A D,8true))((C O N F U S E,8true))

## PARI/GP

BLOCKS = "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM";

can_make_word(w) = check(Vecsmall(BLOCKS), Vecsmall(w))

check(B,W,l=1,n=1) =
{
if (l > #W, return(1), n > #B, return(0));

forstep (i = 1, #B-2, 2,
if (B[i] != bitand(W[l],223) && B[i+1] != bitand(W[l],223), next());
B[i] = B[i+1] = 0;
if (check(B, W, l+1, n+2), return(1))
);
0
}

for (i = 1, #WORDS, printf("%s\t%d\n", WORDS[i], can_make_word(WORDS[i])));
Output:
A	1
Bark	1
BOOK	0
Treat	1
COMMON	0
conFUSE	1

## Pascal

Works with: Free Pascal version 2.6.2

#!/usr/bin/instantfpc
//program ABCProblem;

{\$mode objfpc}{\$H+}

uses SysUtils, Classes;

const
// every couple of chars is a block
// remove one by replacing its 2 chars by 2 spaces
Blocks = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM';
BlockSize = 3;

function can_make_word(Str: String): boolean;
var
wkBlocks: string = Blocks;
c: Char;
iPos : Integer;
begin
// all chars to uppercase
Str := UpperCase(Str);
Result := Str <> '';
if Result then
begin
for c in Str do
begin
iPos := Pos(c, wkBlocks);
if (iPos > 0) then
begin
// Char found
wkBlocks[iPos] := ' ';
// Remove the other face
if (iPos mod BlockSize = 1) then
wkBlocks[iPos + 1] := ' '
else
wkBlocks[iPos - 1] := ' ';
end
else
begin
// missed
Result := False;
break;
end;
end;
end;
// Debug...
//WriteLn(Blocks);
//WriteLn(wkBlocks);
End;

procedure TestABCProblem(Str: String);
const
boolStr : array[boolean] of String = ('False', 'True');
begin
WriteLn(Format('>>> can_make_word("%s")%s%s', [Str, LineEnding, boolStr[can_make_word(Str)]]));
End;

begin
TestABCProblem('A');
TestABCProblem('BARK');
TestABCProblem('BOOK');
TestABCProblem('TREAT');
TestABCProblem('COMMON');
TestABCProblem('CONFUSE');
END.
Output:
./ABCProblem.pas
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True

## Perl

Recursive solution that can handle characters appearing on different blocks:

#!/usr/bin/perl
use warnings;
use strict;

sub can_make_word {
my (\$word, @blocks) = @_;
\$_ = uc join q(), sort split // for @blocks;
my %blocks;
\$blocks{\$_}++ for @blocks;
return _can_make_word(uc \$word, %blocks)
}

sub _can_make_word {
my (\$word, %blocks) = @_;
my \$char = substr \$word, 0, 1, q();

my @candidates = grep 0 <= index(\$_, \$char), keys %blocks;
for my \$candidate (@candidates) {
next if \$blocks{\$candidate} <= 0;
local \$blocks{\$candidate} = \$blocks{\$candidate} - 1;
return 1 if q() eq \$word or _can_make_word(\$word, %blocks);
}
return
}

Testing:

use Test::More tests => 8;

my @blocks1 = qw(BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM);
is(can_make_word("A", @blocks1), 1);
is(can_make_word("BARK", @blocks1), 1);
is(can_make_word("BOOK", @blocks1), undef);
is(can_make_word("TREAT", @blocks1), 1);
is(can_make_word("COMMON", @blocks1), undef);
is(can_make_word("CONFUSE", @blocks1), 1);

my @blocks2 = qw(US TZ AO QA);
is(can_make_word('auto', @blocks2), 1);

### Regex based alternate

#!/usr/bin/perl

use strict; # https://rosettacode.org/wiki/ABC_Problem
use warnings;

printf "%30s  %s\n", \$_, can_make_word( \$_,
'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM' )
for qw( A BARK BOOK TREAT COMMON SQUAD CONFUSE );

sub can_make_word
{
my (\$word, \$blocks) = @_;
my \$letter = chop \$word or return 'True';
can_make_word( \$word, \$` . \$' ) eq 'True' and return 'True'
while \$blocks =~ /\w?\$letter\w?/gi;
return 'False';
}
Output:
A  True
BARK  True
BOOK  False
TREAT  True
COMMON  False
CONFUSE  True

## Phix

Recursive solution which also solves the extra problems on the discussion page.

sequence blocks, words, used

function ABC_Solve(sequence word, integer idx)
integer ch, res = 0
if idx>length(word) then
res = 1
-- or:  res = length(word)>0 -- (if "" -> false desired)
else
ch = word[idx]
for k=1 to length(blocks) do
if used[k]=0
and find(ch,blocks[k]) then
used[k] = 1
res = ABC_Solve(word,idx+1)
used[k] = 0
if res then exit end if
end if
end for
end if
return res
end function

constant tests = {{{"BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS",
"JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"},
{{"US","TZ","AO","QA"},{"AuTO"}},
{{"AB","AB","AC","AC"},{"abba"}}}

for i=1 to length(tests) do
{blocks,words} = tests[i]
used = repeat(0,length(blocks))
for j=1 to length(words) do
printf(1,"%s: %t\n",{words[j],ABC_Solve(upper(words[j]),1)})
end for
end for
Output:
: true
A: true
BarK: true
BOOK: false
TrEaT: true
COMMON: false
CONFUSE: true
AuTO: true
abba: true

## PHP

<?php
\$words = array("A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse");

function canMakeWord(\$word) {
\$word = strtoupper(\$word);
\$blocks = array(
"BO", "XK", "DQ", "CP", "NA",
"GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB",
"ER", "FS", "LY", "PC", "ZM",
);

foreach (str_split(\$word) as \$char) {
foreach (\$blocks as \$k => \$block) {
if (strpos(\$block, \$char) !== FALSE) {
unset(\$blocks[\$k]);
continue(2);
}
}
return false;
}
return true;
}

foreach (\$words as \$word) {
echo \$word.': ';
echo canMakeWord(\$word) ? "True" : "False";
echo "\r\n";
}
Output:
A: True
BARK: True
BOOK: False
TREAT: True
COMMON: False
Confuse: True

## Picat

Showing both a Picat style version (check_word/2) and a Prolog style recursive version (check_word2/2). go2/0 generates all possible solutions (using fail/0) to backtrack.

go =>
test_it(check_word),
test_it(check_word2),
nl.

% Get all possible solutions (via fail)
go2 ?=>
test_version(check_word2),
fail,
nl.
go2 => true.

%
% Test a version.
%
test_it(Pred) =>
println(testing=Pred),
Blocks = findall([A,B], block(A,B)),
Words = findall(W,word(W)),
foreach(Word in Words)
println(word=Word),
( call(Pred,Word,Blocks) ; println("Cannot make word.")),
nl
end,
nl.

%
% Picat style: Using nth/3 for getting the chars
%
check_word(Word, Blocks) =>
WordC = atom_chars(Word), % convert atom to string
WordLen = length(WordC),
X = new_list(WordLen),
Pos = new_list(WordLen),
foreach(I in 1..WordLen)
% find a character at the specific position
nth(X[I],Blocks,XI),
nth(Pos[I],XI, WordC[I])
end,
alldiff(X), % ensure unique selection
foreach(I in 1..WordLen)
println([WordC[I], Blocks[X[I]]])
end,
nl.

%
% Prolog style (recursive) version using select/3.
% (where we don't have to worry about duplicate blocks)
%
check_word2(Word, Blocks) :-
pick_block(atom_chars(Word),Blocks,[],X),
println(X).

pick_block([], _,Res,Res).
pick_block([C|WordRest], Blocks, Res1,[Block|Res]) :-
% pick (non-deterministically) one of the blocks
select(Block,Blocks,BlocksRest),
membchk(C,Block),
pick_block(WordRest,BlocksRest,Res1,Res).

%
% alldiff(L):
% ensure that all elements in L are different
%
alldiff([]).
alldiff([_]).
alldiff([H|T]) :-
neq(H,T),
alldiff(T).

neq(_,[]).
neq(X,[H|T]) :-
X != H,
neq(X,T).

% The words to check.
word(a).
word(bark).
word(book).
word(treat).
word(common).
word(confuse).
word(auto).
word(abba).
word(coestablishment).
word(schoolmastering).

% The blocks
block(b,o).
block(x,k).
block(d,q).
block(c,p).
block(n,a).
block(g,t).
block(r,e).
block(t,g).
block(q,d).
block(f,s).
block(j,w).
block(h,u).
block(v,i).
block(a,n).
block(o,b).
block(e,r).
block(f,s).
block(l,y).
block(p,c).
block(z,m).

Output:
testing = check_word
word = a
[a,na]

word = bark
[b,bo] [a,na] [r,re] [k,xk]

word = book
Cannot make word.

word = treat
[t,gt] [r,re] [e,er] [a,na] [t,tg]

word = common
Cannot make word.

[s,fs] [q,dq] [u,hu] [a,na] [d,qd]

word = confuse
[c,cp] [o,bo] [n,na] [f,fs] [u,hu] [s,fs] [e,re]

word = auto
[a,na] [u,hu] [t,gt] [o,bo]

word = abba
[a,na] [b,bo] [b,ob] [a,an]

word = coestablishment
[c,cp] [o,bo] [e,re] [s,fs] [t,gt] [a,na] [b,ob] [l,ly] [i,vi] [s,fs] [h,hu] [m,zm] [e,er] [n,an] [t,tg]

word = schoolmastering
[s,fs] [c,cp] [h,hu] [o,bo] [o,ob] [l,ly] [m,zm] [a,na] [s,fs] [t,gt] [e,re] [r,er] [i,vi] [n,an] [g,tg]

testing = check_word2
word = a
[na]

word = bark
[bo,na,re,xk]

word = book
Cannot make word.

word = treat
[gt,re,er,na,tg]

word = common
Cannot make word.

[fs,dq,hu,na,qd]

word = confuse
[cp,bo,na,fs,hu,fs,re]

word = auto
[na,hu,gt,bo]

word = abba
[na,bo,ob,an]

word = coestablishment
[cp,bo,re,fs,gt,na,ob,ly,vi,fs,hu,zm,er,an,tg]

word = schoolmastering
[fs,cp,hu,bo,ob,ly,zm,na,fs,gt,re,er,vi,an,tg]

## PicoLisp

Mapping and recursion.

(setq *Blocks
'((B O) (X K) (D Q) (C P) (N A) (G T) (R E)
(T G) (Q D) (F S) (J W) (H U) (V I) (A N)
(O B) (E R) (F S) (L Y) (P C) (Z M) ) )
(setq *Words '("" "1" "A" "BARK" "BOOK" "TREAT"
"Bbb" "COMMON" "SQUAD" "Confuse"
"abba" "ANBOCPDQERSFTGUVWXLZ") )

(de abc (W B)
(let Myblocks (copy B)
(fully
'((C)
(when (seek '((Lst) (member C (car Lst))) Myblocks)
(set @)
T ) )
(chop (uppc W)) ) ) )

(de abcR (W B)
(nond
((car W) T)
((car B) NIL)
(NIL
(setq W (chop W))
(let? I
(find
'((Lst) (member (uppc (car W)) Lst))
B )
(abcR (cdr W) (delete I B)) ) ) ) )

(for Word *Words
(println Word (abc Word *Blocks) (abcR Word *Blocks)) )

(bye)

## PL/I

### version 1

ABC: procedure options (main);   /* 12 January 2014 */

declare word character (20) varying, blocks character (200) varying initial
('((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G) (Q D) (F S)
(J W) (H U) (V I) (A N) (O B) (E R) (F S) (L Y) (P C) (Z M))'
);
declare tblocks character (200) varying;
declare (true value ('1'b), false value ('0'b), flag) bit (1);
declare ch character (1);
declare (i, k) fixed binary;

do word = 'A', 'BARK', 'BOOK', 'TREAT', 'COMMON', 'SQuAd', 'CONFUSE';
flag = true;
tblocks = blocks;
do i = 1 to length(word)
while(flag = true);
ch = substr(word, i, 1);
k = index(tblocks, uppercase(ch));
if k = 0 then
flag = false;
else /* Found a block with the letter on it. */
substr(tblocks, k-1, 4) = ' '; /* Delete the block. */
end;
if flag then put skip list (word, 'true'); else put skip list (word, 'false');
end;

end ABC;
A                       true
BARK                    true
BOOK                    false
TREAT                   true
COMMON                  false
CONFUSE                 true

### version 2

*process source attributes xref or(!) options nest;
abc: Proc Options(main);
/* REXX --------------------------------------------------------------
* 10.01.2013 Walter Pachl counts the number of possible ways
* translated from Rexx version 2
*-------------------------------------------------------------------*/

Dcl sysprint Print;
Dcl (i,j,k,m,mm,wi,wj,wlen,ways,lw) Bin Fixed(15);
Dcl blocks(20) Char(2)
Init('BO','XK','DQ','CP','NA','GT','RE','TG','QD','FS','JW',
'HU','VI','AN','OB','ER','FS','LY','PC','ZM');
Dcl blk Char(2);
Dcl words(8) Char(7) Var
Dcl word Char(7) Var;
Dcl c Char(1);
Dcl (show,cannot) Bit(1) Init('0'b);
Dcl poss(100,0:100) Pic'99'; poss=0;
Dcl s(20,100) char(100) Var;
Dcl str Char(100);
Dcl 1 *(30) Based(addr(str)),
2 strp Pic'99',
2 * Char(1);
Dcl ns(20) Bin Fixed(15) Init((20)0);
Dcl ol(100) Char(100) Var;
Dcl os Char(100) Var;
wlen=0;
Dcl lower Char(26) Init('abcdefghijklmnopqrstuvwxyz');
Dcl upper Char(26) Init('ABCDEFGHIJKLMNOPQRSTUVWXYZ');
Do wi=1 To hbound(words);
wlen=max(wlen,length(words(wi)));
End;
Do wi=1 To hbound(words);
word = translate(words(wi),upper,lower);
ways=0;
lw=length(word);
cannot='0'b;
poss=0;
ns=0;
ol='';
iloop:
Do i=1 To lw; /* loop over the characters */
c=substr(word,i,1); /* the current character */
Do j=1 To hbound(blocks); /* loop over blocks */
blk=blocks(j);
If index(blk,c)>0 Then Do; /* block can be used in this pos( */
poss(i,0)+=1; /* number of possible blocks for pos i */
poss(i,poss(i,0))=j;
End;
End;
If poss(i,0)=0 Then Do;
Leave iloop;
End;
End;
If i>lw Then Do; /* no prohibitive character */
ns=0;
Do j=1 To poss(1,0); /* build possible strings for char 1 */
ns(1)+=1;;
s(1,j)=poss(1,j);
End;
Do m=2 To lw; /* build possible strings for chars 1 to i */
mm=m-1;
Do j=1 To ns(mm);
Do k=1 To poss(m,0);
ns(m)+=1;
s(m,ns(m))=s(mm,j)!!' '!!poss(m,k);
End;
End;
End;
Do m=1 To ns(lw);
If valid(s(lw,m)) Then Do;
ways+=1;
str=s(lw,m);
Do k=1 To lw;
ol(ways)=ol(ways)!!blocks(strp(k))!!' ';
End;
End;
End;
End;
/*--------------------------------------------------------------------
* now show the result
*-------------------------------------------------------------------*/

os=left(''''!!word!!'''',wlen+2);
Select;
When(ways=0)
os=os!!' cannot be spelt.';
When(ways=1)
os=os!!' can be spelt.';
Otherwise
os=os!!' can be spelt in'!!ways!!' ways.';
End;
Put Skip List(os);
If show Then Do;
Do wj=1 To ways;
Put Edit(' '!!ol(wj))(Skip,a);
End;
End;
End;
Return;

valid: Procedure(list) Returns(bit(1));
/*--------------------------------------------------------------------
* Check if the same block is used more than once -> 0
* Else: the combination is valid
*-------------------------------------------------------------------*/

Dcl list Char(*) Var;
Dcl i Bin Fixed(15);
Dcl used(20) Bit(1);
str=list;
used='0'b;
Do i=1 To lw;
If used(strp(i)) Then
Return('0'b);
used(strp(i))='1'b;
End;
Return('1'b);
End;

End;
Output:
'\$'       cannot be spelt.
'A'       can be spelt in        2 ways.
'BARK'    can be spelt in        8 ways.
'BOOK'    cannot be spelt.
'TREAT'   can be spelt in        8 ways.
'COMMON'  cannot be spelt.
'SQUAD'   can be spelt in        8 ways.
'CONFUSE' can be spelt in       32 ways.

## PL/M

100H:

/* ABC PROBLEM ON \$-TERMINATED STRING */
CAN\$MAKE\$WORD: PROCEDURE (STRING) BYTE;
DECLARE STRING ADDRESS, CHAR BASED STRING BYTE;
DECLARE CONST\$BLOCKS DATA
('BOKXDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM');
DECLARE I BYTE, BLOCKS (40) BYTE;

DO I=0 TO 39; /* MAKE COPY OF BLOCKS */
BLOCKS(I) = CONST\$BLOCKS(I);
END;

STEP: DO WHILE CHAR <> '\$';
DO I=0 TO 39; /* FIND BLOCK WITH CURRENT CHAR */
IF BLOCKS(I) = CHAR THEN DO; /* FOUND IT */
BLOCKS(I) = 0; /* CLEAR OUT BOTH LETTERS ON BLOCK */
BLOCKS(I XOR 1) = 0;
STRING = STRING + 1;
GO TO STEP; /* NEXT CHARACTER */
END;
END;
RETURN 0; /* NO BLOCK WITH LETTER */
END;

RETURN 1; /* WE FOUND THEM ALL */
END CAN\$MAKE\$WORD;

/* CP/M BDOS CALL */
BDOS: PROCEDURE (FN, ARG);
DECLARE FN BYTE, ARG ADDRESS;
GO TO 5;
END BDOS;

PRINT: PROCEDURE (STRING);
CALL BDOS(9, STRING);
END PRINT;

/* TEST SEVERAL STRINGS */
DECLARE TEST (7) ADDRESS, I BYTE;
TEST(0) = .'A\$';
TEST(1) = .'BARK\$';
TEST(2) = .'BOOK\$';
TEST(3) = .'TREAT\$';
TEST(4) = .'COMMON\$';
TEST(6) = .'CONFUSE\$';

DO I = 0 TO LAST(TEST);
CALL PRINT(TEST(I));
CALL PRINT(.': \$');
IF CAN\$MAKE\$WORD(TEST(I))
THEN CALL PRINT(.'YES\$');
ELSE CALL PRINT(.'NO\$');
CALL PRINT(.(13,10,'\$'));
END;

CALL BDOS(0,0);
EOF
Output:
A: YES
BARK: YES
BOOK: NO
TREAT: YES
COMMON: NO
CONFUSE: YES

## PowerBASIC

Works with PowerBASIC 6 Console Compiler

#COMPILE EXE
#DIM ALL
'
' A B C p r o b l e m . b a s
'
' by Geary Chopoff
' for Chopoff Consulting and RosettaCode.org
' on 2014Jul23
'
'2014Jul23
'
'You are given a collection of ABC blocks. Just like the ones you had when you were a kid.
'There are twenty blocks with two letters on each block. You are guaranteed to have a complete
'alphabet amongst all sides of the blocks. The sample blocks are:
'((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G) (Q D) (F S) (J W) (H U) (V I) (A N) (O B) (E R) (F S) (L Y) (P C) (Z M))
'The goal of this task is to write a function that takes a string and can determine whether
'you can spell the word with the given collection of blocks.
'
'The rules are simple:
'1.Once a letter on a block is used that block cannot be used again
'2.The function should be case-insensitive
'3. Show your output on this page for the following words:
' A, BARK, BOOK, TREAT, COMMON, SQUAD, CONFUSE
'-----------------------------------------------------------------------------
' G l o b a l C o n s t a n t s
'
%Verbose = 0 'make this 1 to have a lot of feedback
%MAX_BLOCKS = 20 'total number of blocks
%MAX_SIDES = 2 'total number of sides containing a unique letter per block

%MAX_ASC = 255
%FALSE = 0 'this is correct because there is ONLY ONE value for FALSE
%TRUE = (NOT %FALSE) 'this is one of MANY values of TRUE!
\$FLAG_TRUE = "1"
\$FLAG_FALSE = "0"
'-----------------------------------------------------------------------------
' G l o b a l V a r i a b l e s
'
GLOBAL blk() AS STRING
'-----------------------------------------------------------------------------
'i n i t B l o c k s
'
' as we will use this array only once we build it each time program is run
'
SUB initBlocks
LOCAL j AS INTEGER
j=1
blk(j)="BO"
j=j+1
blk(j)="XK"
j=j+1
blk(j)="DQ"
j=j+1
blk(j)="CP"
j=j+1
blk(j)="NA"
j=j+1
blk(j)="GT"
j=j+1
blk(j)="RE"
j=j+1
blk(j)="TG"
j=j+1
blk(j)="QD"
j=j+1
blk(j)="FS"
j=j+1
blk(j)="JW"
j=j+1
blk(j)="HU"
j=j+1
blk(j)="VI"
j=j+1
blk(j)="AN"
j=j+1
blk(j)="OB"
j=j+1
blk(j)="ER"
j=j+1
blk(j)="FS"
j=j+1
blk(j)="LY"
j=j+1
blk(j)="PC"
j=j+1
blk(j)="ZM"
IF j <> %MAX_BLOCKS THEN
STDOUT "initBlocks:Error: j is not same as MAX_BLOCKS!",j,%MAX_BLOCKS
END IF
END SUB
'-----------------------------------------------------------------------------
' m a k e W o r d
'
FUNCTION makeWord(tryWord AS STRING) AS BYTE
LOCAL retTF AS BYTE
LOCAL j AS INTEGER
LOCAL s AS INTEGER 'which side of block we are looking at
LOCAL k AS INTEGER
LOCAL c AS STRING 'character in tryWord we are looking for

FOR j = 1 TO LEN(tryWord)
c = UCASE\$(MID\$(tryWord,j,1)) 'character we want to show with block

retTF = %FALSE 'we assume this will fail

FOR k = 1 TO %MAX_BLOCKS
IF LEN(blk(k)) = %MAX_SIDES THEN
FOR s = 1 TO %MAX_SIDES
IF c = MID\$(blk(k),s,1) THEN
retTF = %TRUE 'this block has letter we want
blk(k) = "" 'remove this block from further consideration
EXIT FOR
END IF
NEXT s
END IF
IF retTF THEN EXIT FOR 'can go on to next character in word
NEXT k
IF ISFALSE retTF THEN EXIT FOR 'if character not found then all is done
NEXT j

FUNCTION = retTF
END FUNCTION
'-----------------------------------------------------------------------------
' P B M A I N
'
FUNCTION PBMAIN () AS LONG
DIM blk(1 TO %MAX_BLOCKS, 1 TO %MAX_SIDES) AS STRING
LOCAL cmdLine AS STRING

initBlocks 'setup global array of blocks

cmdLine=COMMAND\$
IF LEN(cmdLine)= 0 THEN
STDOUT "Useage for ABCproblem Version 1.00:"
STDOUT ""
STDOUT " >ABCproblem tryThisWord"
STDOUT ""
STDOUT "Where tryThisWord is a word you want to see if"+STR\$(%MAX_BLOCKS)+" blocks can make."
STDOUT "If word can be made TRUE is returned."
STDOUT "Otherwise FALSE is returned."
EXIT FUNCTION
END IF

IF INSTR(TRIM\$(cmdLine)," ") = 0 THEN
IF makeWord(cmdLine) THEN
STDOUT "TRUE"
ELSE
STDOUT "FALSE"
END IF
ELSE
STDOUT "Error:Missing word to try to make with blocks! <" & cmdLine & ">"
EXIT FUNCTION
END IF
END FUNCTION

Output:
\$ FALSE
A TRUE
bark TRUE
bOOk FALSE
treAT TRUE
COmmon FALSE
CONFUSE TRUE
GearyChopoff TRUE

## PowerShell

<#
.Synopsis
ABC Problem
.DESCRIPTION
You are given a collection of ABC blocks. Just like the ones you had when you were a kid.
There are twenty blocks with two letters on each block. You are guaranteed to have a
complete alphabet amongst all sides of the blocks
blocks = "BO","XK","DQ","CP","NA","GT","RE","TG","QD","FS","JW","HU","VI","AN","OB","ER","FS","LY","PC","ZM"
The goal of this task is to write a function that takes a string and can determine whether
you can spell the word with the given collection of blocks.

The rules are simple:
1.Once a letter on a block is used that block cannot be used again
2.The function should be case-insensitive
3. Show your output on this page for the following words:
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True

Using the examples below you can either see just the value or
status and the values using the verbose switch

.EXAMPLE
test-blocks -testword confuse

.EXAMPLE
test-blocks -testword confuse -verbose

#>

function test-blocks
{
[CmdletBinding()]
# [OutputType([int])]
Param
(
# word to test against blocks
[Parameter(Mandatory = \$true,
ValueFromPipelineByPropertyName = \$true)]
\$testword

)

\$word = \$testword

#define array of blocks
[System.Collections.ArrayList]\$blockarray = "BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"

#send word to chararray
\$chararray = \$word.ToCharArray()
\$chars = \$chararray

#get the character count
\$charscount = \$chars.count

#get the initial count of the blocks
\$blockcount = \$blockarray.Count

#find out how many blocks should be left from the difference
#of the blocks and characters in the word - 1 letter/1 block
\$correctblockcount = \$blockcount - \$charscount

#loop through the characters in the word
foreach (\$char in \$chars)
{

#loop through the blocks
foreach (\$block in \$blockarray)
{

#check the current character against each letter on the current block
#and break if found so the array can reload
if (\$char -in \$block[0] -or \$char -in \$block[1])
{

write-verbose "match for letter - \$char - removing block \$block"
\$blockarray.Remove(\$block)
break

}

}

}
#get final count of blocks left in array to determine if the word was
\$finalblockcount = \$blockarray.count
if (\$finalblockcount -ne \$correctblockcount)
{
write-verbose "\$word : \$false "
return \$false
}
else
{
write-verbose "\$word : \$true "
return \$true
}

}

#loop all the words and pass them to the function
\$wordlist = "a", "bark", "book", "treat", "common", "squad", "confuse"
foreach (\$word in \$wordlist)
{
test-blocks -testword \$word -Verbose
}
Output:
VERBOSE: match for letter - a - removing block NA
VERBOSE: a : True
True
VERBOSE: match for letter - b - removing block BO
VERBOSE: match for letter - a - removing block NA
VERBOSE: match for letter - r - removing block RE
VERBOSE: match for letter - k - removing block XK
VERBOSE: bark : True
True
VERBOSE: match for letter - b - removing block BO
VERBOSE: match for letter - o - removing block OB
VERBOSE: match for letter - k - removing block XK
VERBOSE: book : False
False
VERBOSE: match for letter - t - removing block GT
VERBOSE: match for letter - r - removing block RE
VERBOSE: match for letter - e - removing block ER
VERBOSE: match for letter - a - removing block NA
VERBOSE: match for letter - t - removing block TG
VERBOSE: treat : True
True
VERBOSE: match for letter - c - removing block CP
VERBOSE: match for letter - o - removing block BO
VERBOSE: match for letter - m - removing block ZM
VERBOSE: match for letter - o - removing block OB
VERBOSE: match for letter - n - removing block NA
VERBOSE: common : False
False
VERBOSE: match for letter - s - removing block FS
VERBOSE: match for letter - q - removing block DQ
VERBOSE: match for letter - u - removing block HU
VERBOSE: match for letter - a - removing block NA
VERBOSE: match for letter - d - removing block QD
VERBOSE: squad : True
True
VERBOSE: match for letter - c - removing block CP
VERBOSE: match for letter - o - removing block BO
VERBOSE: match for letter - n - removing block NA
VERBOSE: match for letter - f - removing block FS
VERBOSE: match for letter - u - removing block HU
VERBOSE: match for letter - s - removing block FS
VERBOSE: match for letter - e - removing block RE
VERBOSE: confuse : True
True

or without verbose

True
True
False
True
False
True
True

## Prolog

Works with SWI-Prolog 6.5.3

abc_problem :-
maplist(abc_problem, ['', 'A', bark, bOOk, treAT, 'COmmon', sQuaD, 'CONFUSE']).

abc_problem(Word) :-
L = [[b,o],[x,k],[d,q],[c,p],[n,a],[g,t],[r,e],[t,g],[q,d],[f,s],
[j,w],[h,u],[v,i],[a,n],[o,b],[e,r],[f,s],[l,y],[p,c],[z,m]],

( abc_problem(L, Word)
-> format('~w OK~n', [Word])
; format('~w KO~n', [Word])).

abc_problem(L, Word) :-
atom_chars(Word, C_Words),
maplist(downcase_atom, C_Words, D_Words),
can_makeword(L, D_Words).

can_makeword(_L, []).

can_makeword(L, [H | T]) :-
( select([H, _], L, L1); select([_, H], L, L1)),
can_makeword(L1, T).

Output:
?- abc_problem.
OK
A OK
bark OK
bOOk KO
treAT OK
COmmon KO
CONFUSE OK
true.

### Constraint Handling Rules

An approach using [CHR https://dtai.cs.kuleuven.be/CHR/] via SWI-Prolog's [library(chr) http://www.swi-prolog.org/pldoc/man?section=chr] and a module I'm working on for composing predicates composer:

Works with: SWI Prolog 7
:- use_module([ library(chr),
abathslib(protelog/composer) ]).

:- chr_constraint blocks, block/1, letter/1, word_built.

can_build_word(Word) :-
maplist(block, [(b,o),(x,k),(d,q),(c,p),(n,a),(g,t),(r,e),(t,g),(q,d),(f,s),
(j,w),(h,u),(v,i),(a,n),(o,b),(e,r),(f,s),(l,y),(p,c),(z,m)]),
maplist(letter) <- string_chars <- string_lower(Word), %% using the `composer` module
word_built,
!.

'take letter and block' @ letter(L), block((A,B)) <=> L == A ; L == B | true.
'fail if letters remain' @ word_built, letter(_) <=> false.

%% These rules, removing remaining constraints from the store, are just cosmetic:
'clean up blocks' @ word_built \ block(_) <=> true.
'word was built' @ word_built <=> true.

Demonstration:

?- can_build_word("A").
true.
?- can_build_word("BARK").
true.
?- can_build_word("BOOK").
false.
?- can_build_word("TREAT").
true.
?- can_build_word("COMMON").
false.
true.
?- can_build_word("CONFUSE").
true.

## PureBasic

### PureBasic: Iterative

EnableExplicit
#LETTERS = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM "

Procedure.s can_make_word(word.s)
Define letters.s = #LETTERS, buffer.s
Define index1.i, index2.i
Define match.b
For index1=1 To Len(word)
index2=1 : match=#False
Repeat
buffer=StringField(letters,index2,Space(1))
If FindString(buffer,Mid(word,index1,1),1,#PB_String_NoCase)
letters=RemoveString(letters,buffer+Chr(32),0,1,1)
match=#True
Break
EndIf
index2+1
Until index2>CountString(letters,Space(1))
If Not match : ProcedureReturn word+#TAB\$+"FALSE" : EndIf
Next
ProcedureReturn word+#TAB\$+"TRUE"
EndProcedure

OpenConsole()
PrintN(can_make_word("a"))
PrintN(can_make_word("BaRK"))
PrintN(can_make_word("BOoK"))
PrintN(can_make_word("TREAt"))
PrintN(can_make_word("cOMMON"))
PrintN(can_make_word("COnFUSE"))
Input()

### PureBasic: Recursive

#LETTERS = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM "

Macro test(t)
Print(t+#TAB\$+#TAB\$+"= ") : If can_make_word(t) : PrintN("True") : Else : PrintN("False") : EndIf
EndMacro

Procedure.s residue(s\$,n.i)
ProcedureReturn Left(s\$,Int(n/3)*3)+Mid(s\$,Int(n/3)*3+4)
EndProcedure

Procedure.b can_make_word(word\$,letters\$=#LETTERS)
n=FindString(letters\$,Left(word\$,1),1,#PB_String_NoCase)
If Len(word\$) And n : ProcedureReturn can_make_word(Mid(word\$,2),residue(letters\$,n)) : EndIf
If Not Len(word\$)  : ProcedureReturn #True : Else : ProcedureReturn #False  : EndIf
EndProcedure

OpenConsole()
test("a")  : test("BaRK")  : test("BOoK")  : test("TREAt")
test("cOMMON")  : test("SqUAD")  : test("COnFUSE")
Input()
Output:
a               = True
BaRK            = True
BOoK            = False
TREAt           = True
cOMMON          = False
COnFUSE         = True

## Python

### Python: Iterative, with tests

'''
Note that this code is broken, e.g., it won't work when
blocks = [("A", "B"), ("A","C")] and the word is "AB", where the answer
should be True, but the code returns False.
'''

blocks = [("B", "O"),
("X", "K"),
("D", "Q"),
("C", "P"),
("N", "A"),
("G", "T"),
("R", "E"),
("T", "G"),
("Q", "D"),
("F", "S"),
("J", "W"),
("H", "U"),
("V", "I"),
("A", "N"),
("O", "B"),
("E", "R"),
("F", "S"),
("L", "Y"),
("P", "C"),
("Z", "M")]

def can_make_word(word, block_collection=blocks):
"""
Return True if `word` can be made from the blocks in `block_collection`.

>>> can_make_word("")
False
>>> can_make_word("a")
True
>>> can_make_word("bark")
True
>>> can_make_word("book")
False
>>> can_make_word("treat")
True
>>> can_make_word("common")
False
True
>>> can_make_word("coNFused")
True
"""

if not word:
return False

blocks_remaining = block_collection[:]
for char in word.upper():
for block in blocks_remaining:
if char in block:
blocks_remaining.remove(block)
break
else:
return False
return True

if __name__ == "__main__":
import doctest
doctest.testmod()
print(", ".join("'%s': %s" % (w, can_make_word(w)) for w in
["", "a", "baRk", "booK", "treat",

Output:
'': False, 'a': True, 'baRk': True, 'booK': False, 'treat': True, 'COMMON': False, 'squad': True, 'Confused': True

### Python: Recursive

BLOCKS = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'.split()

def _abc(word, blocks):
for i, ch in enumerate(word):
for blk in (b for b in blocks if ch in b):
whatsleft = word[i + 1:]
blksleft = blocks[:]
blksleft.remove(blk)
if not whatsleft:
return True, blksleft
if not blksleft:
return False, blksleft
ans, blksleft = _abc(whatsleft, blksleft)
if ans:
return ans, blksleft
else:
break
return False, blocks

def abc(word, blocks=BLOCKS):
return _abc(word.upper(), blocks)[0]

if __name__ == '__main__':
for word in [''] + 'A BARK BoOK TrEAT COmMoN SQUAD conFUsE'.split():
print('Can we spell %9r? %r' % (word, abc(word)))
Output:
Can we spell       ''? False
Can we spell       'A'? True
Can we spell    'BARK'? True
Can we spell    'BoOK'? False
Can we spell   'TrEAT'? True
Can we spell  'COmMoN'? False
Can we spell   'SQUAD'? True
Can we spell 'conFUsE'? True

### Python: Recursive, telling how

def mkword(w, b):
if not w: return []

c,w = w[0],w[1:]
for i in range(len(b)):
if c in b[i]:
m = mkword(w, b[0:i] + b[i+1:])
if m != None: return [b[i]] + m

def abc(w, blk):
return mkword(w.upper(), [a.upper() for a in blk])

blocks = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'.split()

for w in ", A, bark, book, treat, common, SQUAD, conFUsEd".split(', '):
print '\'' + w + '\'' + ' ->', abc(w, blocks)
Output:

Note the case of empty list returned for empty string; whether it means true or false is up to you.

'' -> []
'A' -> ['NA']
'bark' -> ['BO', 'NA', 'RE', 'XK']
'book' -> None
'treat' -> ['GT', 'RE', 'ER', 'NA', 'TG']
'common' -> None
'SQUAD' -> ['FS', 'DQ', 'HU', 'NA', 'QD']
'conFUsEd' -> ['CP', 'BO', 'NA', 'FS', 'HU', 'FS', 'RE', 'DQ']

## q

The possibility of ‘backtracking’, discussed in the FORTRAN solution above (and not tested by the example set) makes this a classic tree search: wherever there is a choice of blocks from which to pick the next letter, each choice must be tested.

BLOCKS:string`BO`XK`DQ`CP`NA`GT`RE`TG`QD`FS`JW`HU`VI`AN`OB`ER`FS`LY`PC`ZM

cmw:{[s;b] / [str;blocks]
\$[0=count s; 1b; / empty string
not any found:any each b=s 0; 0b; / cannot proceed
any(1_s).z.s/:b(til count b)except/:where found] }
Output:
q)WORDS cmw\:BLOCKS
1101011b

The first expression tests whether the string s is empty. If so, the result is true. This matches two cases: either the string is empty and can be made from any set of blocks; or all its letters have been matched and there is nothing more to check.

The second expression looks in the available blocks b for the first letter of s: the boolean vector found flags any hits. If there are none, the result is false: the string cannot be completed from the available blocks.

The last line searches further. The expression til count b indexes the remaining blocks; and where found are the indexes that have the next letter. The derived function except/: yields a list: each item is a copy of the list of indexes til count b, with one of the found indexes removed. The list of blocks b is applied to each of these index lists; the result is multiple versions of the list of blocks; each has had a different block removed. The cmw function is applied to each of these with the truncated string 1_s. (The expression .z.s refers to the currently-running function, so cmw does not need to know its own name.) The result of these calls is a boolean vector; aggregator any reports if any have succeeded in completing the string.

To meet the requirement for case-insensitivity and to display the results, apply the above within a wrapper.

cmwi:{(`\$x), `false`true cmw . upper each(x;y) }
Output:
q)Words cmwi\:BLOCKS
A true
bark true
BOOK false
Treat true
COMMON false
CONFUSE true

## Quackery

### Iterative, without backtracking

See note in the FORTRAN solution and elsewhere re: backtracking. Fails the ABBA test, see "Greedy Algorithm" in the discussion for this page.

This solution assumes the constraint that if a letter appears on more than one block those blocks are identical (as in the example set) so backtracking is not required.

[ \$ "BOXKDQCPNAGTRETGQDFS"
\$ "JWHUVIANOBERFSLYPCZM"
join ] constant is blocks ( --> \$ )

[ -2 &
tuck pluck drop
swap pluck drop ] is remove2 ( \$ n --> \$ )

[ iff [ say "True" ]
else [ say "False" ] ] is echotruth ( b --> )

[ true blocks rot
witheach
[ upper over find
2dup swap found
iff remove2
else
[ drop dip not
conclude ] ]
drop echotruth ] is can_make_word ( \$ --> )

Testing in the Quackery shell:

/O> \$ "A" can_make_word
...
True
Stack empty.

/O> \$ "BARK" can_make_word
...
True
Stack empty.

/O> \$ "BOOK" can_make_word
...
False
Stack empty.

/O> \$ "TREAT" can_make_word
...
True
Stack empty.

/O> \$ "COMMON" can_make_word
...
False
Stack empty.

/O> \$ "SQUAD" can_make_word
...
True
Stack empty.

/O> \$ "CONFUSE" can_make_word
...
True
Stack empty.

### Recursive, with backtracking

See note in the FORTRAN solution and elsewhere re: backtracking. Passes the ABBA test, see "Greedy Algorithm" in the discussion for this page.

This solution does not assume the constraint that if a letter appears on more than one block those blocks are identical (as in the example set) so backtracking is required.

[ ' [ 0 ] swap
witheach
[ over -1 peek
+ join ]
behead drop ] is accumulate ( [ --> [ )

[ [] swap
witheach
[ swap dip
[ over + ]
swap join ]
nip ] is add ( n [ --> [ )

[ [] unrot
[ 2dup find
2dup swap
found while
1+ split
swap size
dip rot join
unrot again ]
2drop drop
accumulate
-1 swap add ] is findall ( x [ --> [ )

[ iff [ say "True" ]
else [ say "False" ] ] is echotruth ( b --> )

[ \$ "BOXKDQCPNAGTRETGQDFS"
\$ "JWHUVIANOBERFSLYPCZM"
join ] constant is blocks ( --> \$ )

[ -2 &
tuck pluck drop
swap pluck drop ] is remove2 ( \$ n --> \$ )

forward is (abc)

[ dup [] = if bail
dip over swap findall
witheach
[ dip over
remove2
over (abc) ]
2drop ] resolves (abc) ( \$ \$ --> )

[ blocks swap
2 backup (abc)
bailed dup
if [ dip 2drop ]
echotruth ] is can_make_word ( \$ --> )

Testing in the Quackery shell: Identical to iterative solution above.

## R

### With recursion

Vectorised function for R which will take a character vector and return a logical vector of equal length with TRUE and FALSE as appropriate for words which can/cannot be made with the blocks.

blocks <- rbind(c("B","O"),
c("X","K"),
c("D","Q"),
c("C","P"),
c("N","A"),
c("G","T"),
c("R","E"),
c("T","G"),
c("Q","D"),
c("F","S"),
c("J","W"),
c("H","U"),
c("V","I"),
c("A","N"),
c("O","B"),
c("E","R"),
c("F","S"),
c("L","Y"),
c("P","C"),
c("Z","M"))

canMake <- function(x) {
x <- toupper(x)
used <- rep(FALSE, dim(blocks)[1L])
charList <- strsplit(x, character(0))
tryChars <- function(chars, pos, used, inUse=NA) {
if (pos > length(chars)) {
TRUE
} else {
used[inUse] <- TRUE
possible <- which(blocks == chars[pos] & !used, arr.ind=TRUE)[, 1L]
any(vapply(possible, function(possBlock) tryChars(chars, pos + 1, used, possBlock), logical(1)))
}
}
setNames(vapply(charList, tryChars, logical(1), 1L, used), x)
}
canMake(c("A",
"BARK",
"BOOK",
"TREAT",
"COMMON",
"CONFUSE"))
Output:
A    BARK    BOOK   TREAT  COMMON   SQUAD CONFUSE
TRUE    TRUE   FALSE    TRUE   FALSE    TRUE    TRUE

### Without recursion

Second version without recursion and giving every unique combination of blocks for each word:

canMakeNoRecursion <- function(x) {
x <- toupper(x)
charList <- strsplit(x, character(0))
getCombos <- function(chars) {
charBlocks <- data.matrix(expand.grid(lapply(chars, function(char) which(blocks == char, arr.ind=TRUE)[, 1L])))
charBlocks <- charBlocks[!apply(charBlocks, 1, function(row) any(duplicated(row))), , drop=FALSE]
if (dim(charBlocks)[1L] > 0L) {
t(apply(charBlocks, 1, function(row) apply(blocks[row, , drop=FALSE], 1, paste, collapse="")))
} else {
character(0)
}
}
setNames(lapply(charList, getCombos), x)
}
canMakeNoRecursion(c("A",
"BARK",
"BOOK",
"TREAT",
"COMMON",
"CONFUSE"))
Output:
\$A
[,1] [,2]
[1,] "AN" "NA"

\$BARK
[,1] [,2] [,3] [,4]
[1,] "BO" "AN" "RE" "XK"
[2,] "OB" "AN" "RE" "XK"
[3,] "BO" "NA" "RE" "XK"
[4,] "OB" "NA" "RE" "XK"
[5,] "BO" "AN" "ER" "XK"
[6,] "OB" "AN" "ER" "XK"
[7,] "BO" "NA" "ER" "XK"
[8,] "OB" "NA" "ER" "XK"

\$BOOK
character(0)

\$TREAT
[,1] [,2] [,3] [,4] [,5]
[1,] "GT" "RE" "ER" "AN" "TG"
[2,] "GT" "ER" "RE" "AN" "TG"
[3,] "GT" "RE" "ER" "NA" "TG"
[4,] "GT" "ER" "RE" "NA" "TG"
[5,] "TG" "RE" "ER" "AN" "GT"
[6,] "TG" "ER" "RE" "AN" "GT"
[7,] "TG" "RE" "ER" "NA" "GT"
[8,] "TG" "ER" "RE" "NA" "GT"

\$COMMON
character(0)

[,1] [,2] [,3] [,4] [,5]
[1,] "FS" "QD" "HU" "AN" "DQ"
[2,] "FS" "QD" "HU" "AN" "DQ"
[3,] "FS" "QD" "HU" "NA" "DQ"
[4,] "FS" "QD" "HU" "NA" "DQ"
[5,] "FS" "DQ" "HU" "AN" "QD"
[6,] "FS" "DQ" "HU" "AN" "QD"
[7,] "FS" "DQ" "HU" "NA" "QD"
[8,] "FS" "DQ" "HU" "NA" "QD"

\$CONFUSE
[,1] [,2] [,3] [,4] [,5] [,6] [,7]
[1,] "CP" "OB" "NA" "FS" "HU" "FS" "ER"
[2,] "PC" "OB" "NA" "FS" "HU" "FS" "ER"
[3,] "CP" "BO" "NA" "FS" "HU" "FS" "ER"
[4,] "PC" "BO" "NA" "FS" "HU" "FS" "ER"
[5,] "CP" "OB" "AN" "FS" "HU" "FS" "ER"
[6,] "PC" "OB" "AN" "FS" "HU" "FS" "ER"
[7,] "CP" "BO" "AN" "FS" "HU" "FS" "ER"
[8,] "PC" "BO" "AN" "FS" "HU" "FS" "ER"
[9,] "CP" "OB" "NA" "FS" "HU" "FS" "ER"
[10,] "PC" "OB" "NA" "FS" "HU" "FS" "ER"
[11,] "CP" "BO" "NA" "FS" "HU" "FS" "ER"
[12,] "PC" "BO" "NA" "FS" "HU" "FS" "ER"
[13,] "CP" "OB" "AN" "FS" "HU" "FS" "ER"
[14,] "PC" "OB" "AN" "FS" "HU" "FS" "ER"
[15,] "CP" "BO" "AN" "FS" "HU" "FS" "ER"
[16,] "PC" "BO" "AN" "FS" "HU" "FS" "ER"
[17,] "CP" "OB" "NA" "FS" "HU" "FS" "RE"
[18,] "PC" "OB" "NA" "FS" "HU" "FS" "RE"
[19,] "CP" "BO" "NA" "FS" "HU" "FS" "RE"
[20,] "PC" "BO" "NA" "FS" "HU" "FS" "RE"
[21,] "CP" "OB" "AN" "FS" "HU" "FS" "RE"
[22,] "PC" "OB" "AN" "FS" "HU" "FS" "RE"
[23,] "CP" "BO" "AN" "FS" "HU" "FS" "RE"
[24,] "PC" "BO" "AN" "FS" "HU" "FS" "RE"
[25,] "CP" "OB" "NA" "FS" "HU" "FS" "RE"
[26,] "PC" "OB" "NA" "FS" "HU" "FS" "RE"
[27,] "CP" "BO" "NA" "FS" "HU" "FS" "RE"
[28,] "PC" "BO" "NA" "FS" "HU" "FS" "RE"
[29,] "CP" "OB" "AN" "FS" "HU" "FS" "RE"
[30,] "PC" "OB" "AN" "FS" "HU" "FS" "RE"
[31,] "CP" "BO" "AN" "FS" "HU" "FS" "RE"
[32,] "PC" "BO" "AN" "FS" "HU" "FS" "RE"

## Racket

I believe you can make an empty word by using no blocks. So '(can-make-word? "")' is true for me.

#lang racket
(define block-strings
(list "BO" "XK" "DQ" "CP" "NA"
"GT" "RE" "TG" "QD" "FS"
"JW" "HU" "VI" "AN" "OB"
"ER" "FS" "LY" "PC" "ZM"))
(define BLOCKS (map string->list block-strings))

(define (can-make-word? w)
(define (usable-block blocks word-char)
(for/first ((b (in-list blocks)) #:when (memf (curry char-ci=? word-char) b)) b))

(define (inner word-chars blocks tried-blocks)
(cond
[(null? word-chars) #t]
[(usable-block blocks (car word-chars))
=>
(lambda (b)
(or
(inner (cdr word-chars) (append tried-blocks (remove b blocks)) null)
(inner word-chars (remove b blocks) (cons b tried-blocks))))]
[else #f]))
(inner (string->list w) BLOCKS null))

(define WORD-LIST '("" "A" "BARK" "BOOK" "TREAT" "COMMON" "SQUAD" "CONFUSE"))
(define (report-word w)
(printf "Can we make: ~a? ~a~%"
(~s w #:min-width 9)
(if (can-make-word? w) "yes" "no")))

(module+ main
(for-each report-word WORD-LIST))

(module+ test
(require rackunit)
(check-true (can-make-word? ""))
(check-true (can-make-word? "A"))
(check-true (can-make-word? "BARK"))
(check-false (can-make-word? "BOOK"))
(check-true (can-make-word? "TREAT"))
(check-false (can-make-word? "COMMON"))
(check-true (can-make-word? "CONFUSE")))
Output:
Can we make: ""       ? yes
Can we make: "A"      ? yes
Can we make: "BARK"   ? yes
Can we make: "BOOK"   ? no
Can we make: "TREAT"  ? yes
Can we make: "COMMON" ? no
Can we make: "SQUAD"  ? yes
Can we make: "CONFUSE"? yes

## Raku

(formerly Perl 6)

Works with: rakudo version 6.0.c

Blocks are stored as precompiled regexes. We do an initial pass on the blockset to include in the list only those regexes that match somewhere in the current word. Conveniently, regexes scan the word for us.

multi can-spell-word(Str \$word, @blocks) {
my @regex = @blocks.map({ my @c = .comb; rx/<@c>/ }).grep: { .ACCEPTS(\$word.uc) }
can-spell-word \$word.uc.comb.list, @regex;
}

multi can-spell-word([\$head,*@tail], @regex) {
for @regex -> \$re {
if \$head ~~ \$re {
return True unless @tail;
return False if @regex == 1;
return True if can-spell-word @tail, list @regex.grep: * !=== \$re;
}
}
False;
}

my @b = <BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM>;

for <A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE> {
say "\$_ &can-spell-word(\$_, @b)";
}
Output:
A	True
BaRK	True
BOoK	False
tREaT	True
COmMOn	False
CoNfuSE	True

## RapidQ

dim Blocks as string
dim InWord as string

Function CanMakeWord (FInWord as string, FBlocks as string) as integer
dim WIndex as integer, BIndex as integer

FBlocks = UCase\$(FBlocks) - " " - ","
FInWord = UCase\$(FInWord)

for WIndex = 1 to len(FInWord)
BIndex = instr(FBlocks, FInWord[WIndex])

if BIndex then
FBlocks = Replace\$(FBlocks,"**",iif(BIndex mod 2,BIndex,BIndex-1))
else
Result = 0
exit function
end if
next

Result = 1
end function

InWord = "Confuse"
Blocks = "BO, XK, DQ, CP, NA, GT, RE, TG, QD, FS, JW, HU, VI, AN, OB, ER, FS, LY, PC, ZM"
showmessage "Can make: " + InWord + " = " + iif(CanMakeWord(InWord, Blocks), "True", "False")

Output:
Can make: A = TRUE
Can make: BARK = TRUE
Can make: BOOK = FALSE
Can make: TREAT = TRUE
Can make: COMMON = FALSE
Can make: SQUAD = TRUE
Can make: CONFUSE = TRUE

## Red

Red []
test: func [ s][
p: copy "BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
forever [
if 0 = length? s [ return 'true ]  ;; if string cleared, all chars found/removed
if tail? p [ return 'false ]  ;; if at end of search block - not found
rule: reduce [ first p '| second p]  ;; construct parse rule from string
either parse s [ to rule remove rule to end ] [  ;; remove found char from string
remove/part p 2  ;;character found , remove block
p: head p  ;;start from remaining string at beginning aka head
] [ p: skip p 2 ]  ;; else move to next block
]
]
foreach word split {A bark book TrEAT COmMoN SQUAD conFUsE} space [
print reduce [ pad copy word 8 ":" test word]
]

Output:
A        : true
bark     : true
book     : false
TrEAT    : true
COmMoN   : false
conFUsE  : true

## REXX

### version 1

/*REXX pgm finds if words can be spelt from a pool of toy blocks (each having 2 letters)*/
list= 'A bark bOOk treat common squaD conFuse' /*words can be: upper/lower/mixed case*/
blocks= 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'
do k=1 for words(list) /*traipse through a list of some words.*/
call spell word(list, k) /*display if word can be spelt (or not)*/
end /*k*/ /* [↑] tests each word in the list. */
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
spell: procedure expose blocks; arg x /*ARG uppercases the word to be spelt.*/
L= length(x); @.= 0 /*get length of the word to be spelt. */
do try=1 for L; z= blocks; upper z /*use a fresh copy of the "Z" blocks.*/
do n=1 for L; y= substr(x, n, 1) /*attempt another letter in the word. */
@.n= pos(y, z, 1 + @.n); if @.n==0 then leave /*not found? Try again*/
z= overlay(' ', z, @.n) /*mutate the toy block ───► a onesy. */
do q=1 for words(z); if length(word(z,q))==1 then z= delword(z, q, 1)
end /*q*/ /* [↑] elide any existing onesy block.*/
if n==L then leave try /*was last letter used in the spelling?*/
end /*n*/ /* [↑] end of a toy block usage. */
end /*try*/ /* [↑] end of a "TRY" permute. */
say right( arg(1), 30) right( word( "can't can", (n==L) + 1), 6) 'be spelt.'
return
output   when using the default inputs:
A    can be spelt.
bark    can be spelt.
bOOk  can't be spelt.
treat    can be spelt.
common  can't be spelt.
squaD    can be spelt.
conFuse    can be spelt.

### version 2

/* REXX ---------------------------------------------------------------
* 10.01.2014 Walter Pachl counts the number of possible ways
* 12.01.2014 corrected date and output
*--------------------------------------------------------------------*/

show=(arg(1)<>'')
blocks = 'BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM'
list = '\$ A baRk bOOk trEat coMMon squaD conFuse'
list=translate(list)
Do i=1 To words(blocks)
blkn.i=word(blocks,i)'-'i
blk.i=word(blocks,i)
End
w.=''
wlen=0
Do i=1 To words(list)
w.i=word(list,i)
wlen=max(wlen,length(w.i))
End
Do wi=0 To words(list)
word = w.wi
ways=0
poss.=0
lw=length(word)
cannot=0
Do i=1 To lw /* loop over the characters */
c=substr(word,i,1) /* the current character */
Do j=1 To words(blocks) /* loop over blocks */
blk=word(blocks,j)
If pos(c,blk)>0 Then Do /* block can be used in this position */
z=poss.i.0+1
poss.i.z=j
poss.i.0=z /* number of possible blocks for pos i */
End
End
If poss.i.0=0 Then Do
cannot=1
Leave i
End
End

If cannot=0 Then Do /* no prohibitive character */
s.=0
Do j=1 To poss.1.0 /* build possible strings for char 1 */
z=s.1.0+1
s.1.z=poss.1.j
s.1.0=z
End
Do i=2 To lw /* build possible strings for chars 1 to i */
ii=i-1
Do j=1 To poss.i.0
Do k=1 To s.ii.0
z=s.i.0+1
s.i.z=s.ii.k poss.i.j
s.i.0=z
End
End
End
Do p=1 To s.lw.0 /* loop through all possible strings */
v=valid(s.lw.p) /* test if the string is valid*/
If v Then Do /* it is */
ways=ways+1 /* increment number of ways */
way.ways='' /* and store the string's blocks */
Do ii=1 To lw
z=word(s.lw.p,ii)
way.ways=way.ways blk.z
End
End
End
End
/*---------------------------------------------------------------------
* now show the result
*--------------------------------------------------------------------*/

ol=left(''''word'''',wlen+2)
Select
When ways=0 Then
ol=ol 'cannot be spelt'
When ways=1 Then
ol=ol 'can be spelt'
Otherwise
ol=ol 'can be spelt in' ways 'ways'
End
Say ol'.'
If show Then Do
Do wj=1 To ways
Say copies(' ',10) way.wj
End
End
End
Exit

valid: Procedure
/*---------------------------------------------------------------------
* Check if the same block is used more than once -> 0
* Else: the combination is valid
*--------------------------------------------------------------------*/

Parse Arg list
used.=0
Do i=1 To words(list)
w=word(list,i)
If used.w Then Return 0
used.w=1
End
Return 1
Output:
''        cannot be spelt.
'\$'       cannot be spelt.
'A'       can be spelt in 2 ways.
'BARK'    can be spelt in 8 ways.
'BOOK'    cannot be spelt.
'TREAT'   can be spelt in 8 ways.
'COMMON'  cannot be spelt.
'SQUAD'   can be spelt in 8 ways.
'CONFUSE' can be spelt in 32 ways.
Output:
extended
''        cannot be spelt.
'\$'       cannot be spelt.
'A'       can be spelt in 2 ways.
NA
AN
'BARK'    can be spelt in 8 ways.
BO NA RE XK
OB NA RE XK
BO AN RE XK
OB AN RE XK
BO NA ER XK
OB NA ER XK
BO AN ER XK
OB AN ER XK
'BOOK'    cannot be spelt.
'TREAT'   can be spelt in 8 ways.
TG ER RE NA GT
TG RE ER NA GT
TG ER RE AN GT
TG RE ER AN GT
GT ER RE NA TG
GT RE ER NA TG
GT ER RE AN TG
GT RE ER AN TG
'COMMON'  cannot be spelt.
'SQUAD'   can be spelt in 8 ways.
FS QD HU NA DQ
FS QD HU NA DQ
FS QD HU AN DQ
FS QD HU AN DQ
FS DQ HU NA QD
FS DQ HU NA QD
FS DQ HU AN QD
FS DQ HU AN QD
'CONFUSE' can be spelt in 32 ways.
CP BO NA FS HU FS RE
PC BO NA FS HU FS RE
CP OB NA FS HU FS RE
PC OB NA FS HU FS RE
CP BO AN FS HU FS RE
PC BO AN FS HU FS RE
CP OB AN FS HU FS RE
PC OB AN FS HU FS RE
CP BO NA FS HU FS RE
PC BO NA FS HU FS RE
CP OB NA FS HU FS RE
PC OB NA FS HU FS RE
CP BO AN FS HU FS RE
PC BO AN FS HU FS RE
CP OB AN FS HU FS RE
PC OB AN FS HU FS RE
CP BO NA FS HU FS ER
PC BO NA FS HU FS ER
CP OB NA FS HU FS ER
PC OB NA FS HU FS ER
CP BO AN FS HU FS ER
PC BO AN FS HU FS ER
CP OB AN FS HU FS ER
PC OB AN FS HU FS ER
CP BO NA FS HU FS ER
PC BO NA FS HU FS ER
CP OB NA FS HU FS ER
PC OB NA FS HU FS ER
CP BO AN FS HU FS ER
PC BO AN FS HU FS ER
CP OB AN FS HU FS ER
PC OB AN FS HU FS ER

## Ring

Blocks = [ :BO, :XK, :DQ, :CP, :NA, :GT, :RE, :TG, :QD, :FS, :JW, :HU, :VI, :AN, :OB, :ER, :FS, :LY, :PC, :ZM ]
Words = [ :A, :BARK, :BOOK, :TREAT, :COMMON, :SQUAD, :CONFUSE ]

for x in words
see '>>> can_make_word("' + upper(x) + '")' + nl
if checkword(x,blocks) see "True" + nl
else see "False" + nl
ok
next

func CheckWord Word,Blocks
cBlocks = BLocks
for x in word
Found = false
for y = 1 to len(cblocks)
if x = cblocks[y][1] or x = cblocks[y][2]
cblocks[y] = "--"
found = true
exit
ok
next
if found = false return false ok
next
return true
Output:
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True

## Ruby

This one uses a case insensitive regular expression. The 'sub!' method substitutes the first substring it finds and returns nil if nothing is found.

words = %w(A BaRK BOoK tREaT COmMOn SqUAD CoNfuSE) << ""

words.each do |word|
blocks = "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM"
res = word.each_char.all?{|c| blocks.sub!(/\w?#{c}\w?/i, "")} #regexps can be interpolated like strings
puts "#{word.inspect}: #{res}"
end

Output:
"A": true
"BaRK": true
"BOoK": false
"tREaT": true
"COmMOn": false
"CoNfuSE": true
"": true

## Run BASIC

blocks\$    = "BO,XK,DQ,CP,NA,GT,RE,TG,QD,FS,JW,HU,VI,AN,OB,ER,FS,LY,PC,ZM"
b = int((len(blocks\$) /3) + 1)
dim blk\$(b)

for i = 1 to len(makeWord\$)
wrd\$ = word\$(makeWord\$,i,",")
dim hit(b)
n = 0
if wrd\$ = "" then exit for
for k = 1 to len(wrd\$)
w\$ = upper\$(mid\$(wrd\$,k,1))
for j = 1 to b
if hit(j) = 0 then
if w\$ = left\$(word\$(blocks\$,j,","),1) or w\$ = right\$(word\$(blocks\$,j,","),1) then
hit(j) = 1
n = n + 1
exit for
end if
end if
next j
next k
print wrd\$;chr\$(9);
if n = len(wrd\$) then print " True" else print " False"
next i
A	 True
BARK	 True
BOOK	 False
TREAT	 True
COMMON	 False
Confuse	 True

## Rust

This implementation uses a backtracking search.

use std::iter::repeat;

fn rec_can_make_word(index: usize, word: &str, blocks: &[&str], used: &mut[bool]) -> bool {
let c = word.chars().nth(index).unwrap().to_uppercase().next().unwrap();
for i in 0..blocks.len() {
if !used[i] && blocks[i].chars().any(|s| s == c) {
used[i] = true;
if index == 0 || rec_can_make_word(index - 1, word, blocks, used) {
return true;
}
used[i] = false;
}
}
false
}

fn can_make_word(word: &str, blocks: &[&str]) -> bool {
return rec_can_make_word(word.chars().count() - 1, word, blocks,
&mut repeat(false).take(blocks.len()).collect::<Vec<_>>());
}

fn main() {
let blocks = [("BO"), ("XK"), ("DQ"), ("CP"), ("NA"), ("GT"), ("RE"), ("TG"), ("QD"), ("FS"),
("JW"), ("HU"), ("VI"), ("AN"), ("OB"), ("ER"), ("FS"), ("LY"), ("PC"), ("ZM")];
let words = ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"];
for word in &words {
println!("{} -> {}", word, can_make_word(word, &blocks))
}
}

Output:
A -> true
BARK -> true
BOOK -> false
TREAT -> true
COMMON -> false
CONFUSE -> true

## Scala

Library: Scala
object AbcBlocks extends App {

protected class Block(face1: Char, face2: Char) {

def isFacedWith(that: Char) = { that == face1 || that == face2 }
override def toString() = face1.toString + face2
}
protected object Block {
def apply(faces: String) = new Block(faces.head, faces.last)
}

type word = Seq[Block]

private val blocks = List(Block("BO"), Block("XK"), Block("DQ"), Block("CP"), Block("NA"),
Block("GT"), Block("RE"), Block("TG"), Block("QD"), Block("FS"),
Block("JW"), Block("HU"), Block("VI"), Block("AN"), Block("OB"),
Block("ER"), Block("FS"), Block("LY"), Block("PC"), Block("ZM"))

private def isMakeable(word: String, blocks: word) = {

def getTheBlocks(word: String, blocks: word) = {

def inner(word: String, toCompare: word, rest: word, accu: word): word = {
if (word.isEmpty || rest.isEmpty || toCompare.isEmpty) accu
val restant = rest diff List(toCompare.head)
inner(word.tail, restant, restant, accu :+ toCompare.head)
} else inner(word, toCompare.tail, rest, accu)
}
inner(word, blocks, blocks, Nil)
}

word.lengthCompare(getTheBlocks(word, blocks).size) == 0
}

val words = List("A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSED", "ANBOCPDQERSFTGUVWXLZ")
// Automatic tests
assert(isMakeable(words(0), blocks))
assert(isMakeable(words(1), blocks))
assert(!isMakeable(words(2), blocks)) // BOOK not
assert(isMakeable(words(3), blocks))
assert(!isMakeable(words(4), blocks)) // COMMON not
assert(isMakeable(words(5), blocks))
assert(isMakeable(words(6), blocks))
assert(isMakeable(words(7), blocks))

//words(7).mkString.permutations.foreach(s => assert(isMakeable(s, blocks)))

words.foreach(w => println(s"\$w can\${if (isMakeable(w, blocks)) " " else "not "}be made."))
}

## Scheme

In R5RS:

(define *blocks*
'((#\B #\O) (#\X #\K) (#\D #\Q) (#\C #\P) (#\N #\A)
(#\G #\T) (#\R #\E) (#\T #\G) (#\Q #\D) (#\F #\S)
(#\J #\W) (#\H #\U) (#\V #\I) (#\A #\N) (#\O #\B)
(#\E #\R) (#\F #\S) (#\L #\Y) (#\P #\C) (#\Z #\M)))

(define (exists p? li)
(and (not (null? li))
(or (p? (car li))
(exists p? (cdr li)))))

(define (remove-one x li)
(cond
((null? li) '())
((equal? (car li) x) (cdr li))
(else (cons (car li) (remove-one x (cdr li))))))

(define (can-make-list? li blocks)
(or (null? li)
(exists
(lambda (block)
(and
(member (char-upcase (car li)) block)
(can-make-list? (cdr li) (remove-one block blocks))))
blocks)))

(define (can-make-word? word)
(can-make-list? (string->list word) *blocks*))

(define *words*
'("A" "Bark" "book" "TrEaT" "COMMON" "squaD" "CONFUSE"))

(for-each
(lambda (word)
(display (if (can-make-word? word)
" Can make word: "
"Cannot make word: "))
(display word)
(newline))
*words*)
Output:
Can make word: A
Can make word: Bark
Cannot make word: book
Can make word: TrEaT
Cannot make word: COMMON
Can make word: squaD
Can make word: CONFUSE

## Seed7

\$ include "seed7_05.s7i";

const func boolean: canMakeWords (in array string: blocks, in string: word) is func
result
var boolean: okay is FALSE;
local
var integer: index is 1;
begin
if word = "" then
okay := TRUE;
elsif length(blocks) <> 0 then
while index <= length(blocks) and not okay do
if blocks[index][1] = word[1] or blocks[index][2] = word[1] then
okay := canMakeWords(blocks[.. pred(index)] & blocks[succ(index) ..], word[2 ..]);
end if;
incr(index);
end while;
end if;
end func;

const array string: blocks is [] ("BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM");

const func boolean: canMakeWords (in string: word) is
return canMakeWords(blocks, upper(word));

const proc: main is func
local
var string: word is "";
begin
for word range [] ("", "A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse") do
writeln(word rpad 10 <& canMakeWords(word));
end for;
end func;
Output:
TRUE
A         TRUE
BARK      TRUE
BOOK      FALSE
TREAT     TRUE
COMMON    FALSE
Confuse   TRUE

## SenseTalk

function CanMakeWord word

put [
("B", "O"),
("X", "K"),
("D", "Q"),
("C", "P"),
("N", "A"),
("G", "T"),
("R", "E"),
("T", "G"),
("Q", "D"),
("F", "S"),
("J", "W"),
("H", "U"),
("V", "I"),
("A", "N"),
("O", "B"),
("E", "R"),
("F", "S"),
("L", "Y"),
("P", "C"),
("Z", "M")
] into blocks

repeat with each character letter of word
put False into found
repeat with each item block of blocks by reference
if item 1 of block is letter ignoring case or item 2 of block is letter ignoring case
delete block
put True into found
exit repeat
end if
end repeat
if found is False
return False
end if
end repeat
return True

end CanMakeWord
repeat with each item word in [
"A",
"BARK",
"BOOK",
"TREAT",
"COMMON",
"CONFUSE"
]
put CanMakeWord(word)
end repeat

## SequenceL

### Recursive Search Version

import <Utilities/Conversion.sl>;
import <Utilities/Sequence.sl>;

main(args(2)) :=
let
result[i] := args[i] ++ ": " ++ boolToString(can_make_word(args[i], InitBlocks));
in
delimit(result, '\n');

InitBlocks := ["BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS", "JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"];

can_make_word(word(1), blocks(2)) :=
let
choices[i] := i when some(blocks[i] = toUpper(head(word)));
blocksAfterChoice[i] := blocks[(1 ... (choices[i] - 1)) ++ ((choices[i] + 1) ... size(blocks))];
in
true when size(word) = 0
else
false when size(choices) = 0
else
some(can_make_word(tail(word), blocksAfterChoice));

toUpper(letter(0)) :=
let
ascii := asciiToInt(letter);
in
letter when ascii >= 65 and ascii <= 90
else
intToAscii(ascii - 32);
Output:
cmd:> main.exe A BARK BOOK TREAT COMMON SQUAD CONFUSE
"A: true
BARK: true
BOOK: false
TREAT: true
COMMON: false
CONFUSE: true"

### RegEx Version

import <Utilities/Conversion.sl>;
import <Utilities/Sequence.sl>;
import <RegEx/RegEx.sl>;

main(args(2)) :=
let
result[i] := args[i] ++ ": " ++ boolToString(can_make_word(args[i], InitBlocks));
in
delimit(result, '\n');

InitBlocks := "BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM";

can_make_word(word(1), blocks(1)) :=
let
regEx := "(\\a" ++ [toUpper(head(word))] ++ "|" ++ [toUpper(head(word))] ++ "\\a)";

newBlocks := replaceFirst(blocks, regEx, "");
in
true when size(word) = 0
else
false when size(newBlocks) = size(blocks)
else
can_make_word(tail(word), newBlocks);

toUpper(letter(0)) :=
let
ascii := asciiToInt(letter);
in
letter when ascii >= 65 and ascii <= 90
else
intToAscii(ascii - 32);

## Sidef

Translation of: Perl
func can_make_word(word, blocks) {

blocks.map! { |b| b.uc.chars.sort.join }.freq!

func(word, blocks) {
var char = word.shift
var candidates = blocks.keys.grep { |k| 0 <= k.index(char) }

for candidate in candidates {
blocks{candidate} <= 0 && next;
local blocks{candidate} = (blocks{candidate} - 1);
return true if (word.is_empty || __FUNC__(word, blocks));
}

return false;
}(word.uc.chars, blocks)
}

Tests:

var b1 = %w(BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM)
var b2 = %w(US TZ AO QA)

var tests = [
["A", true, b1],
["BARK", true, b1],
["BOOK", false, b1],
["TREAT", true, b1],
["COMMON", false, b1],
["CONFUSE", true, b1],
["auto", true, b2],
];

tests.each { |t|
var bool = can_make_word(t[0], t[2]);
say ("%7s -> %s" % (t[0], bool));
assert(bool == t[1])
}
Output:
A -> true
BARK -> true
BOOK -> false
TREAT -> true
COMMON -> false
CONFUSE -> true
auto -> true

## Simula

COMMENT ABC PROBLEM;
BEGIN

CLASS BLOCK(CH1, CH2); CHARACTER CH1, CH2;
BEGIN
BOOLEAN USED;
END;

CLASS GAME(WORD, POSSIBLE); TEXT WORD; BOOLEAN POSSIBLE;;

BOOLEAN PROCEDURE CANMAKEWORD(WORD); TEXT WORD;
BEGIN
INTEGER I, NUMBLOCKS;
BOOLEAN ALLPOSSIBLE, FOUND;
NUMBLOCKS := UPPERBOUND(BLOCKS, 1);
FOR I := 1 STEP 1 UNTIL NUMBLOCKS DO
BLOCKS(I).USED := FALSE;
ALLPOSSIBLE := TRUE;

WORD.SETPOS(1);
WHILE ALLPOSSIBLE AND WORD.MORE DO
BEGIN
CHARACTER WORDCHAR;
WORDCHAR := WORD.GETCHAR;
FOUND := FALSE;
FOR I := 1 STEP 1 UNTIL NUMBLOCKS DO
BEGIN
INSPECT BLOCKS(I) DO
BEGIN
IF (WORDCHAR = CH1 OR WORDCHAR = CH2) AND NOT USED THEN
BEGIN
USED := FOUND := TRUE;
GOTO L;
END;
END;
END;
L:
ALLPOSSIBLE := FALSE;
END;
CANMAKEWORD := ALLPOSSIBLE;
END CANMAKEWORD;

REF(BLOCK) ARRAY BLOCKS(1:20);
REF(GAME) ARRAY GAMES(1:7);
TEXT WORD;
BEGIN
INTEGER I;
I := I+1; BLOCKS(I) :- NEW BLOCK('B', 'O');
I := I+1; BLOCKS(I) :- NEW BLOCK('X', 'K');
I := I+1; BLOCKS(I) :- NEW BLOCK('D', 'Q');
I := I+1; BLOCKS(I) :- NEW BLOCK('C', 'P');
I := I+1; BLOCKS(I) :- NEW BLOCK('N', 'A');
I := I+1; BLOCKS(I) :- NEW BLOCK('G', 'T');
I := I+1; BLOCKS(I) :- NEW BLOCK('R', 'E');
I := I+1; BLOCKS(I) :- NEW BLOCK('T', 'G');
I := I+1; BLOCKS(I) :- NEW BLOCK('Q', 'D');
I := I+1; BLOCKS(I) :- NEW BLOCK('F', 'S');
I := I+1; BLOCKS(I) :- NEW BLOCK('J', 'W');
I := I+1; BLOCKS(I) :- NEW BLOCK('H', 'U');
I := I+1; BLOCKS(I) :- NEW BLOCK('V', 'I');
I := I+1; BLOCKS(I) :- NEW BLOCK('A', 'N');
I := I+1; BLOCKS(I) :- NEW BLOCK('O', 'B');
I := I+1; BLOCKS(I) :- NEW BLOCK('E', 'R');
I := I+1; BLOCKS(I) :- NEW BLOCK('F', 'S');
I := I+1; BLOCKS(I) :- NEW BLOCK('L', 'Y');
I := I+1; BLOCKS(I) :- NEW BLOCK('P', 'C');
I := I+1; BLOCKS(I) :- NEW BLOCK('Z', 'M');
END;
BEGIN
INTEGER N, I; BOOLEAN ANSWER;
N := N+1; GAMES(N) :- NEW GAME("A", TRUE);
N := N+1; GAMES(N) :- NEW GAME("BARK", TRUE);
N := N+1; GAMES(N) :- NEW GAME("BOOK", FALSE);
N := N+1; GAMES(N) :- NEW GAME("TREAT", TRUE);
N := N+1; GAMES(N) :- NEW GAME("COMMON", FALSE);
N := N+1; GAMES(N) :- NEW GAME("SQUAD", TRUE);
N := N+1; GAMES(N) :- NEW GAME("CONFUSE", TRUE);
FOR I := 1 STEP 1 UNTIL N DO
BEGIN
INSPECT GAMES(I) DO
BEGIN
OUTTEXT(WORD);
OUTTEXT(" => ");
OUTCHAR(IF ANSWER THEN 'T' ELSE 'F');
IF ANSWER EQV POSSIBLE
THEN OUTTEXT(" OK")
ELSE OUTTEXT(" ------------- WRONG!");
OUTIMAGE;
END;
END;
END;

END.

Output:
A => T OK
BARK => T OK
BOOK => F OK
TREAT => T OK
COMMON => F OK
SQUAD => T OK
CONFUSE => T OK

## Smalltalk

Recursive solution. Tested in Pharo.

ABCPuzzle>>test
#('A' 'BARK' 'BOOK' 'TreaT' 'COMMON' 'sQUAD' 'CONFuSE') do: [ :each |
Transcript crShow: each, ': ', (self solveFor: each) asString ]

ABCPuzzle>>solveFor: letters
| blocks |
blocks := #('BO' 'XK' 'DQ' 'CP' 'NA' 'GT' 'RE' 'TG' 'QD' 'FS' 'JW' 'HU' 'VI' 'AN' 'OB' 'ER' 'FS' 'LY' 'PC' 'ZM').
^ self solveFor: letters asUppercase with: blocks asOrderedCollection

ABCPuzzle>>solveFor: letters with: blocks
| l ldash matches |
letters isEmpty ifTrue: [ ^ true ].
l := letters first.
ldash := letters allButFirst.
matches := blocks select: [  :b | b includes: l ].
matches isEmpty ifTrue: [ ^ false ].
matches do: [  :m | | bdash |
bdash := blocks copy.
bdash remove: m.
(self solveFor: ldash with: bdash) ifTrue: [ ^ true ] ].
^ false

Output:
ABCPuzzle new test

A: true
BARK: true
BOOK: false
TreaT: true
COMMON: false
CONFuSE: true

## SNOBOL4

* Program: abc.sbl,
* To run: sbl -r abc.sbl
* Comment: Tested using the Spitbol for Linux version of SNOBOL4

* Read in blocks to construct the blocks string
in1
line = replace(input,&lcase,&ucase) :f(in1end)
line ? breakx(' ') . pre ' ' rem . post :f(in1end)
blocks = blocks "," pre post
:(in1)
in1end

* Function to determine if a word can be constructed with the given blocks
define('abc(blocks,word)s,i,let')
abcpat = (breakx(',') ',') . pre (*let len(1) | len(1) *let) rem . post
:(abc_end)
abc
eq(size(word),0) :s(abc3)
s = replace(word,&lcase,&ucase)
i = 0
abc2
i = lt(i,size(s)) i + 1 :f(abc4)
let = substr(s,i,1)
blocks ? abcpat = pre post :f(abc3)
:(abc2)
abc3
abc = 'False' :(abc5)
abc4
abc = 'True'  :(abc5)
abc5
output = lpad('can_make_word("' word '"): ',26) abc
abc = ""
:(return)
abc_end

* Check words
* output = abc(blocks,"")
* output = abc(blocks," ")
output = abc(blocks,'A')
output = abc(blocks,'bark')
output = abc(blocks,'BOOK')
output = abc(blocks,'TrEAT')
output = abc(blocks,'COMMON')
output = abc(blocks,'CONFUSE')

* The blocks are entered below, after the following END label
END
b o
X K
D Q
C P
N A
G T
R E
T G
Q D
F S
J W
H U
V I
A N
O B
E R
F S
L Y
P C
Z M

Output:
can_make_word("A"): True

can_make_word("bark"): True

can_make_word("BOOK"): False

can_make_word("TrEAT"): True

can_make_word("COMMON"): False

can_make_word("CONFUSE"): True

blocks:List Tuple Symbol:= _
[(B,O),(X,K),(D,Q),(C,P),(N,A),(G,T),(R,E),(T,G),(Q,D),(F,S), _
(J,W),(H,U),(V,I),(A,N),(O,B),(E,R),(F,S),(L,Y),(P,C),(Z,M)]

findComb(l:List List NNI):List List NNI ==
#l=0 => []
#l=1 => [[s] for s in first l]
r:List List NNI:=[]
for y in findComb(rest l) repeat
r:=concat(r,[concat(x,y) for x in first l])
return r

canMakeWord?(word,blocks) ==
word:=upperCase word
bchr:=[map(char,map(string,s::List(Symbol))) for s in blocks]
c:=[[j for j in 1..#blocks | member?(word.k,bchr.j)] for k in 1..#word]
reduce(_or,[test(#removeDuplicates(l)=#word) for l in findComb(c)])

[canMakeWord?(s,blocks) for s in Example]

Programming details:UserGuide

Output:
[true,true,false,true,false,true,true]
Type: List(Boolean)

There is optimization potential of course.

## Standard ML

val BLOCKS = [(#"B",#"O"), (#"X",#"K"), (#"D",#"Q"), (#"C",#"P"), (#"N",#"A"), (#"G",#"T"),
(#"R",#"E"), (#"T",#"G"), (#"Q",#"D"), (#"F",#"S"), (#"J",#"W"), (#"H",#"U"), (#"V",#"I"),
(#"A",#"N"),(#"O",#"B"), (#"E",#"R"), (#"F",#"S"), (#"L",#"Y"), (#"P",#"C"), (#"Z",#"M")];
val words = ["A","BARK","BOOK","TREaT","COMMON","SQUAD","CONFUSE"];
open List;

local
val remove = fn x => fn B => (fn (a,b) => (tl a)@b ) (partition ( fn a=> x=a) B)
in
fun cando ([] , Done, B ) = true
| cando (h::t, Done, []) = false
| cando (h::t, Done, B ) =
let
val S = find (fn (a,b) => a=h orelse b=h) B
in
if isSome S then cando (t, (h,valOf S)::Done, remove (valOf S) B)
else
let
val T = find ( fn(_,(a,b)) => a=h orelse b=h) Done
val U = if isSome T then find (fn (a,b) => a = #1 (valOf T) orelse b = #1 (valOf T) ) B else NONE
in
if isSome T andalso isSome U
then cando ( t, (#1 (valOf T),(valOf U))::(h,#2 (valOf T))::(remove (valOf T) Done), remove (valOf U) B)
else false
end
end
end;

map (fn st => cando(map Char.toUpper (String.explode st),[],BLOCKS)) words;

val BLOCKS = [(#"U",#"S"), (#"T",#"Z"), (#"A",#"O"), (#"Q",#"A")];
val words = ["A","UTAH","AutO"];
map (fn st => cando(map Char.toUpper (String.explode st),[],BLOCKS)) words;

Output

val it = [true, true, false, true, false, true, true]: bool list
val it = [true, false, true]: bool list

## Swift

import Foundation

func Blockable(str: String) -> Bool {

var blocks = [
"BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM" ]

var strUp = str.uppercaseString
var final = ""

for char: Character in strUp {
var CharString: String = ""; CharString.append(char)
for j in 0..<blocks.count {
if blocks[j].hasPrefix(CharString) ||
blocks[j].hasSuffix(CharString) {
final.append(char)
blocks[j] = ""
break
}
}
}

return final == strUp
}

func CanOrNot(can: Bool) -> String {
return can ? "can" : "cannot"
}

for str in [ "A", "BARK", "BooK", "TrEaT", "comMON", "sQuAd", "Confuse" ] {
println("'\(str)' \(CanOrNot(Blockable(str))) be spelled with blocks.")
}
Output:
'A' can be spelled with blocks.
'BARK' can be spelled with blocks.
'BooK' cannot be spelled with blocks.
'TrEaT' can be spelled with blocks.
'comMON' cannot be spelled with blocks.
'sQuAd' can be spelled with blocks.
'Confuse' can be spelled with blocks.
Works with: Swift version 3.0.2
import Swift

func canMake(word: String) -> Bool {
var blocks = [
"BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM"
]

for letter in word.uppercased().characters {
guard let index = blocks.index(where: { \$0.characters.contains(letter) }) else {
return false
}

blocks.remove(at: index)
}

return true
}

let words = ["a", "bARK", "boOK", "TreAt", "CoMmon", "SquAd", "CONFUse"]

words.forEach { print(\$0, canMake(word: \$0)) }
Output:
A true
BARK true
BooK false
TrEaT true
comMON false
Confuse true

## Tcl

Works with: Tcl version 8.6
package require Tcl 8.6

proc abc {word {blocks {BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM}}} {
set abc {{letters blocks abc} {
set rest [lassign \$letters ch]
set i 0
foreach blk \$blocks {
if {\$ch in \$blk && (![llength \$rest]
|| [apply \$abc \$rest [lreplace \$blocks \$i \$i] \$abc])} {
return true
}
incr i
}
return false
}}
return [apply \$abc [split \$word ""] [lmap b \$blocks {split \$b ""}] \$abc]
}

foreach word {"" A BARK BOOK TREAT COMMON SQUAD CONFUSE} {
puts [format "Can we spell %9s? %s" '\$word' [abc \$word]]
}
Output:
Can we spell        ''? false
Can we spell       'A'? true
Can we spell    'BARK'? true
Can we spell    'BOOK'? false
Can we spell   'TREAT'? true
Can we spell  'COMMON'? false
Can we spell   'SQUAD'? true
Can we spell 'CONFUSE'? true

## TUSCRIPT

set words = "A'BARK'BOOK'TREAT'COMMON'SQUAD'CONFUSE"
set result = *
loop word = words
set blocks = "BO'XK'DQ'CP'NA'GT'RE'TG'QD'FS'JW'HU'VI'AN'OB'ER'FS'LY'PC'ZM"
set wordx = split (word, |"~</~")
set cond = "true"
loop char = wordx
set n = filter_index (blocks, "~*{char}*~", -)
if (n.eq."") then
set cond = "false"
exit
endif
set n2 = select (n, 1)
set n3 = select (blocks, #n2, blocks)
endloop
set out = concat (word, " ", cond)
set result = append (result, out)
endloop
Output:
A true
BARK true
BOOK false
TREAT true
COMMON false
CONFUSE true

## TXR

@(do
(defvar blocks '((B O) (X K) (D Q) (C P) (N A) (G T) (R E) (T G)
(Q D) (F S) (J W) (H U) (V I) (A N) (O B) (E R)
(F S) (L Y) (P C) (Z M)))

;; Define and build hash which maps each letter that occurs in blocks
;; to a list of the blocks in which that letter occurs.

(defvar alpha2blocks [hash-uni [group-by first blocks]
[group-by second blocks]
append])

;; convert, e.g. "abc" -> (A B C)
;; intern -- convert a string to an interned symbol "A" -> A
;; tuples -- turn string into 1-element tuples: "ABC" -> ("A" "B" "C")
;; square brackets around mapcar -- Lisp-1 style evaluation, allowing
;; the intern function binding to be treated as a variable binding.

(defun string-to-syms (str)
[mapcar intern (tuples 1 (upcase-str str))])

;; Recursive part of algorithm working purely with Lisp symbols.
;; alpha -- single symbol denoting a letter
;; [alpha2blocks alpha] -- look up list of blocks for given letter
;; (memq item list) -- is item a member of list, under eq equality?
;; (remq item list) -- remove items from list which are eq to item.

(defun can-make-word-guts (letters blocks)
(cond
((null letters) t)
((null blocks) nil)
(t (let ((alpha (first letters)))
(each ((bl [alpha2blocks alpha]))
(if (and (memq bl blocks)
(can-make-word-guts (rest letters)
(remq bl blocks)))
(return-from can-make-word-guts t)))))))

(defun can-make-word (str)
(can-make-word-guts (string-to-syms str) blocks)))
@(repeat)
@w
@(output)
>>> can_make_word("@(upcase-str w)")
@(if (can-make-word w) "True" "False")
@(end)
@(end)

Run:

\$ cat abc-problem.data
a
bark
book
treat
common
confuse
\$ txr abc-problem.txr abc-problem.data
>>> can_make_word("A")
True
>>> can_make_word("BARK")
True
>>> can_make_word("BOOK")
False
>>> can_make_word("TREAT")
True
>>> can_make_word("COMMON")
False
True
>>> can_make_word("CONFUSE")
True

## Ultimate++

This is example is a slight modification of the C and C++ examples. To avoid warning "<bold>warning: ISO C++11 does not allow conversion from string literal to 'char *' [-Wwritable-strings]</bold> the strings added to char were individually prefixed with (char*). Swap is used instead of SWAP. Return 0 was not not needed.

#include <Core/Core.h>
#include <stdio.h>
#include <ctype.h>
//C++
#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <cctype>

//C++
typedef std::pair<char,char> item_t;
typedef std::vector<item_t> list_t;

//C
using namespace Upp;

int can_make_words(char **b, char *word)
{
int i, ret = 0, c = toupper(*word);

if (!c) return 1;
if (!b[0]) return 0;

for (i = 0; b[i] && !ret; i++) {
if (b[i][0] != c && b[i][1] != c) continue;
Swap(b[i], b[0]); // It needs to be Swap and not SWAP
ret = can_make_words(b + 1, word + 1);
Swap(b[i], b[0]); // It needs to be Swap instead of SWAP
}
return ret;
}

//C++

bool can_create_word(const std::string& w, const list_t& vals) {
std::set<uint32_t> used;
while (used.size() < w.size()) {
const char c = toupper(w[used.size()]);
uint32_t x = used.size();
for (uint32_t i = 0, ii = vals.size(); i < ii; ++i) {
if (used.find(i) == used.end()) {
if (toupper(vals[i].first) == c || toupper(vals[i].second) == c) {
used.insert(i);
break;
}
}
}
if (x == used.size()) break;
}
return used.size() == w.size();
}

// U++
CONSOLE_APP_MAIN
{
// C
char* blocks[] =
{
(char*)"BO", (char*)"XK", (char*)"DQ", (char*)"CP",
(char*)"NA", (char*)"GT", (char*)"RE", (char*)"TG",
(char*)"QD", (char*)"FS", (char*)"JW", (char*)"HU",
(char*)"VI", (char*)"AN", (char*)"OB", (char*)"ER",
(char*)"FS", (char*)"LY", (char*)"PC", (char*)"ZM", 0
};

char *words[] =
{
(char*)"", (char*)"A", (char*)"BARK", (char*)"BOOK",
(char*)"TREAT", (char*)"COMMON", (char*)"SQUAD", (char*)"Confuse", 0
};

char **w;
for (w = words; *w; w++)
printf("%s\t%d\n", *w, can_make_words(blocks, *w));

printf("\n");

// C++
list_t vals{ {'B', 'O'}, {'X', 'K'}, {'D', 'Q'}, {'C', 'P'},
{'N', 'A'}, {'G', 'T'}, {'R', 'E'}, {'T', 'G'}, {'Q', 'D'},
{'F', 'S'}, {'J', 'W'}, {'H', 'U'}, {'V', 'I'}, {'A', 'N'},
{'O', 'B'}, {'E', 'R'}, {'F', 'S'}, {'L', 'Y'}, {'P', 'C'},
{'Z', 'M'}
};
std::vector<std::string> wordsb{"A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "Confuse"};
for (const std::string& w : wordsb) {
std::cout << w << ": " << std::boolalpha << can_create_word(w, vals) << ".\n";
}
std::cout << "\n";

const Vector<String>& cmdline = CommandLine();
for(int i = 0; i < cmdline.GetCount(); i++) {
}

}

Output:
1
A       1
BARK    1
BOOK    0
TREAT   1
COMMON  0
Confuse 1

A: true.
BARK: true.
BOOK: false.
TREAT: true.
COMMON: false.
Confuse: true.

<--- Finished in (0:00.53), exitcode: 0 --->

## UNIX Shell

Works with: bash
can_build_word() {
if [[ \$1 ]]; then
can_build_word_rec "\$1" BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM
else
return 1
fi
}

can_build_word_rec() {
[[ -z \$1 ]] && return 0

local -u word=\$1 # uppercase the first parameter
shift
local blocks=()

# see if we have a block for the first letter
local letter=\${word:0:1} indices=() i
for (( i=0; i<\${#blocks[@]}; i++ )); do
if [[ \${blocks[i]} == *\$letter* ]]; then
indices+=(\$i)
fi
done
(( \${#indices[@]} == 0 )) && return 1

local tmp
for i in \${indices[@]}; do
tmp=( "\${blocks[@]}" )
unset "tmp[\$i]"
can_build_word_rec "\${word:1}" "\${tmp[@]}" && return 0
done

return 1
}

words=( "" A BARK Book treat COMMON Squad confuse )
for word in "\${words[@]}"; do
can_build_word "\$word" "\${blocks[@]}" && ans=yes || ans=no
printf "%s\t%s\n" "\$word" \$ans
done
Output:
no
A	yes
BARK	yes
Book	no
treat	yes
COMMON	no
confuse	yes

## UTFool

String-based solution

···
http://rosettacode.org/wiki/ABC_Problem
···
■ ABC
§ static
blocks⦂ StringBuffer " BO XK DQ CP NA GT RE TG QD FS
JW HU VI AN OB ER FS LY PC ZM"
▶ main
• args⦂ String[]
for each word in ["A", "BARK", "BOOK", "TREAT",
"COMMON", "SQUAD", "CONFUSE"]⦂ String

System.out.println "⸨word⸩: ⸨canMakeWord word⸩"

▶ canMakeWord⦂ boolean
• word⦂ String
solution⦂ boolean: word.isEmpty°
if no solution
i⦂ int: blocks.indexOf word.substring 0, 1
🔁 until solution or i < 0
i: i ÷ 3 × 3 · block index
block⦂ String: blocks.substring i, i + 3
blocks.delete i, i + 3 · remove block
solution: canMakeWord word.substring 1
blocks.insert i, block · restore block
i: blocks.indexOf (word.substring 0, 1), i + 3
return solution

Collection-based solution

···
http://rosettacode.org/wiki/ABC_Problem
···
import java.util.Arrays
import java.util.Collections
import java.util.List
■ ABC
§ static
▶ main
• args⦂ String[]
blocks⦂ List⟨String⟩:
Arrays.asList "BO", "XK", "DQ", "CP", "NA",
"GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB",
"ER", "FS", "LY", "PC", "ZM"
words⦂ List⟨String⟩:
Arrays.asList "A", "BARK", "BOOK", "TREAT",
for each word in words
System.out.println "⸨word⸩: ⸨canMakeWord word, blocks⸩"

▶ canMakeWord⦂ boolean
• word⦂ String
• blocks⦂ List⟨String⟩
if word.isEmpty°
return true
for each block #i in blocks⦂ String
if 0 ≤ block.indexOf word.charAt 0
Collections.swap blocks, 0, i
if canMakeWord (word.substring 1),
blocks.subList 1, blocks.size°
return true
Collections.swap blocks, 0, i
return false

## VBA

Option Explicit

Sub Main_ABC()
Dim Arr, i As Long

Arr = Array("A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE")
For i = 0 To 6
Debug.Print ">>> can_make_word " & Arr(i) & " => " & ABC(CStr(Arr(i)))
Next i
End Sub

Function ABC(myWord As String) As Boolean
Dim myColl As New Collection
Dim NbLoop As Long, NbInit As Long
Dim b As Byte, i As Byte
Const BLOCKS As String = "B,O;X,K;D,Q;C,P;N,A;G,T;R,E;T,G;Q,D;F,S;J,W;H,U;V,I;A,N;O,B;E,R;F,S;L,Y;P,C;Z,M"

For b = 0 To 19
myColl.Add Split(BLOCKS, ";")(b), Split(BLOCKS, ";")(b) & b
Next b
NbInit = myColl.Count
NbLoop = NbInit
For b = 1 To Len(myWord)
For i = 1 To NbLoop
If i > NbLoop Then Exit For
If InStr(myColl(i), Mid(myWord, b, 1)) <> 0 Then
myColl.Remove (i)
NbLoop = NbLoop - 1
Exit For
End If
Next
Next b
ABC = (NbInit = (myColl.Count + Len(myWord)))
End Function

Output:
>>> can_make_word A => True
>>> can_make_word BARK => True
>>> can_make_word BOOK => False
>>> can_make_word TREAT => True
>>> can_make_word COMMON => False
>>> can_make_word SQUAD => True
>>> can_make_word CONFUSE => True

## Wren

Translation of: Go
Library: Wren-fmt
import "/fmt" for Fmt

var r // recursive
r = Fn.new { |word, bl|
if (word == "") return true
var c = word.bytes[0] | 32
for (i in 0...bl.count) {
var b = bl[i]
if (c == b.bytes[0] | 32 || c == b.bytes[1] | 32) {
bl[i] = bl[0]
bl[0] = b
if (r.call(word[1..-1], bl[1..-1])) return true
var t = bl[i]
bl[i] = bl[0]
bl[0] = t
}
}
return false
}

var newSpeller = Fn.new { |blocks|
var bl = blocks.split(" ")
return Fn.new { |word| r.call(word, bl) }
}

var sp = newSpeller.call("BO XK DQ CP NA GT RE TG QD FS JW HU VI AN OB ER FS LY PC ZM")
for (word in ["A", "BARK", "BOOK", "TREAT", "COMMON", "SQUAD", "CONFUSE"]) {
System.print("%(Fmt.s(-7, word)) %(sp.call(word))")
}
Output:
A       true
BARK    true
BOOK    false
TREAT   true
COMMON  false
CONFUSE true

## XPL0

string 0;

char Side1, Side2;
def Size = 20;
char Avail(Size);

func CanMakeWord(Word); \returns 'true' if blocks can make Word
char Word;
int I, Let;
[Let:= Word(0) & \$5F; \get letter and make sure it's uppercase
if Let = 0 then return true; \if 0 then end of word; return successful
for I:= 0 to Size-1 do \scan for block that contains letter
if Avail(I) and (Side1(I) = Let or Side2(I) = Let) then
[Avail(I):= false;
if CanMakeWord(Word+1) then return true;
];
return false;
];

int I, J, Words;
[Side1:= "BXDCNGRTQFJHVAOEFLPZ";
Side2:= "OKQPATEGDSWUINBRSYCM";
Words:= ["A", "bark", "Book", "Treat", "Common", "Squad", "conFuse"];
for J:= 0 to 6 do
[Text(0, "Can make ^""); Text(0, Words(J)); Text(0, "^": ");
for I:= 0 to Size-1 do Avail(I):= true;
Text(0, if CanMakeWord(Words(J)) then "True" else "False"); CrLf(0);
];
]
Output:
Can make "A": True
Can make "bark": True
Can make "Book": False
Can make "Treat": True
Can make "Common": False
Can make "Squad": True
Can make "conFuse": True

## Yabasic

letters\$ = "BO,XK,DQ,CP,NA,GT,RE,TG,QD,FS,JW,HU,VI,AN,OB,ER,FS,LY,PC,ZM"

sub canMake(letters\$, word\$)
local i, j, p, n, pairs\$(1)

n = token(letters\$, pairs\$(), ",")
word\$ = upper\$(word\$)

for i = 1 to len(word\$)
for j = 1 to n
p = instr(pairs\$(j), mid\$(word\$, i, 1))
if p then
pairs\$(j) = ""
break
end if
next j
if not p return false
next i
return true
end sub

print "a = ", canMake(letters\$, "a") // 1 = true
print "bark = ", canMake(letters\$, "Bark") // 1
print "book = ", canMake(letters\$, "BooK") // 0 = false
print "treat = ", canMake(letters\$, "TREAt") // 1
print "common = ", canMake(letters\$, "common") // 0
print "squad = ", canMake(letters\$, "squad") // 1
print "confuse = ", canMake(letters\$, "confuse") // 1

## zkl

Translation of: C
var blocks=T("BO", "XK", "DQ", "CP", "NA", "GT", "RE", "TG", "QD", "FS",
"JW", "HU", "VI", "AN", "OB", "ER", "FS", "LY", "PC", "ZM", );

fcn can_make_word(word){
fcn(blks,word){
if (not word) return(True); // bottom of recursion
foreach b in (blks){ n:=__bWalker.idx;
if(not b.holds(word[0])) continue; // letter not on this block
blks.del(n); // remove this block from pile
if (self.fcn(blks,word[1,*])) return(True); // try remaining blocks
blks.insert(n,b); // put block back in pile: backtracking
}
False; // out of blocks but not out of word
}(blocks.copy(),word.toUpper())
}

foreach word in (T("","A","BarK","BOOK","TREAT","COMMON","SQUAD","Confuse","abba")){
can_make_word(word).println(": ",word);
}
Output:
True:
True: A
True: BarK
False: BOOK
True: TREAT
False: COMMON
True: Confuse
True: abba

## zonnon

module Main;
type
Block = record
l,r: char;
used: boolean;
end Block;

var
blocks: array 20 of Block;

procedure Exists(c: char): boolean;
var
i: integer;
r: boolean;
begin
r := false;i := 0;
while ~r & (i < len(blocks)) do
if ~(blocks[i].used) then
r := (blocks[i].l = cap(c)) or (blocks[i].r = cap(c));
blocks[i].used := r;
end;
inc(i)
end;
return r
end Exists;

procedure CanMakeWord(s: string);
var
i: integer;
begin
for i := 0 to len(s) - 1 do
end;
Clean()
end CanMakeWord;

procedure Clean();
var
i: integer;
begin
for i := 0 to len(blocks) - 1 do
blocks[i].used := false
end
end Clean;

procedure InitBlock(i:integer;l,r:char);
begin
blocks[i].l := l;blocks[i].r := r;
blocks[i].used := false;
end InitBlock;

procedure Init;
begin
InitBlock(0,'B','O');
InitBlock(1,'X','K');
InitBlock(2,'D','Q');
InitBlock(3,'C','Q');
InitBlock(4,'N','A');
InitBlock(5,'G','T');
InitBlock(6,'R','E');
InitBlock(7,'T','G');
InitBlock(8,'Q','D');
InitBlock(9,'F','S');
InitBlock(10,'J','W');
InitBlock(11,'H','U');
InitBlock(12,'V','I');
InitBlock(13,'A','N');
InitBlock(14,'O','B');
InitBlock(15,'E','R');
InitBlock(16,'F','S');
InitBlock(17,'L','Y');
InitBlock(18,'P','C');
InitBlock(19,'Z','M')
end Init;

begin
Init();
CanMakeWord("A");
CanMakeWord("BARK");
CanMakeWord("BOOK");
CanMakeWord("TREAT");
CanMakeWord("COMMON");
CanMakeWord("confuse");
end Main.

Output:
A   ?  true
BARK   ?  true
BOOK   ? false
TREAT   ?  true
COMMON   ? false
confuse   ?  true

## ZX Spectrum Basic

10 LET b\$="BOXKDQCPNAGTRETGQDFSJWHUVIANOBERFSLYPCZM"
30 FOR c=1 TO p
50 GO SUB 100
60 NEXT c
70 STOP
90 REM Can make?
100 LET u\$=b\$
110 PRINT "Can make word ";p\$;"? ";
120 FOR i=1 TO LEN p\$
130 FOR j=1 TO LEN u\$
140 IF p\$(i)=u\$(j) THEN GO SUB 200: GO TO 160
150 NEXT j
160 IF j>LEN u\$ THEN PRINT "No": RETURN
170 NEXT i
180 PRINT "Yes": RETURN
190 REM Erase pair
200 IF j/2=INT (j/2) THEN LET u\$(j-1 TO j)=" ": RETURN
210 LET u\$(j TO j+1)=" ": RETURN
Output:
Can make word A? Yes
Can make word BARK? Yes
Can make word BOOK? No
Can make word TREAT? Yes
Can make word COMMON? No
Can make word SQUAD? Yes
Can make word CONFYUSE? Yes