Taxicab numbers: Difference between revisions
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Line 3,572:
25 402597 => 56³ + 61³, 42³ + 69³
ok
</pre>
=={{header|RPL}}==
A priority queue allows to get the first 25th taxicab numbers without being killed by the emulator timedog.
{{works with|Halcyon Calc|4.2.7}}
{| class="wikitable"
! Code
! Comments
|-
|
≪
{} 1 PQueue SIZE FOR j
IF OVER j ≠ THEN PQueue j GET 1 →LIST + END
NEXT
'PQueue' STO DROP
≫ 'PQPop' STO
≪
0 {} → idx item
≪ 0 1 PQueue SIZE FOR j
PQueue j GET 1 GET
IF DUP2 <
THEN SWAP PQueue j GET 'item' STO j 'idx' STO
END DROP
NEXT
DROP idx item
≫ ≫ 'PQMax' STO
≪ → pos
1 CF PQueue SIZE WHILE DUP 1 FC? AND REPEAT
IF PQueue OVER GET pos GET 3 PICK == THEN 1 SF END
1 -
END
DROP2 1 FS?
≫ ≫ 'PQin?' STO
≪ OVER 3 ^ OVER 3 ^ + ROT ROT
3 →LIST 1 →LIST PQueue + 'PQueue' STO
≫ 'PQAdd' STO
≪ → item
≪ IF item 1 GET LastItem 1 GET == THEN
{} item 1 GET + item 2 GET item 3 GET R→C +
LastItem 2 GET LastItem 3 GET R→C + 1 →LIST
TaxiNums + 'TaxiNums' STO
END
item 'LastItem' STO
≫ ≫ 'StoreIfTwice' STO
≪ WHILE PQueue SIZE REPEAT
PQMax DUP StoreIfTwice LIST→ DROP 4 ROLL PQPop → r c
≪ IF r 1 >
THEN IF r 1 - 2 PQin? NOT
THEN r 1 - c PQAdd END END
IF c 1 > c r > AND
THEN IF c 1 - 3 PQin? NOT
THEN r c 1 - PQAdd END
END
DROP
≫
END
≫ 'TAXI' STO
≪ → n
≪ { 0 0 0 } 'LastItem' STO
{ } DUP 'PQueue' STO 'TaxiNums' STO n n PQAdd
≫ ≫ 'INIT 'STO
|
''( j -- )''
Scan the priority queue
Copy all items except one
''( -- index { PQ_item } )''
Look for PQ item with max value
''( x pos -- boolean )''
''( r, c -- { PQ_item } )''
''( x pos -- boolean )''
PQ item = { r^3+c^3 r c }
''( -- )''
Removing max value from queue - and store it if déjà vu
can we add an item from the row above?
can we add an item from the left column and above diagonal?
''( magic_number -- )''
initialize global variables
|}
The following commands deliver what is required:
70 INIT TAXI
TaxiNums
{{out}}
<pre>
1: { { 1729 (9,10) (1,12) } { 4104 (9,15) (2,16) } { 13832 (18,20) (2,24) } { 20683 (19,24) (10,27) } { 32832 (18,30) (4,32) } { 39312 (15,33) (2,34) } { 40033 (16,33) (9,34) } { 46683 (27,30) (3,36) } { 64232 (26,36) (17,39) } { 65728 (31,33) (12,40) } { 110656 (36,40) (4,48) } { 110808 (27,45) (6,48) } { 134379 (38,43) (12,51) } { 149389 (29,50) (8,53) } { 165464 (38,48) (20,54) } { 171288 (24,54) (17,55) } { 195841 (22,57) (9,58) } { 216027 (22,59) (3,60) } { 216125 (45,50) (5,60) } { 262656 (36,60) (8,64) } { 314496 (30,66) (4,68) } { 320264 (32,66) (18,68) } { 327763 (51,58) (30,67) } { 402597 (56,61) (42,69) } }
</pre>
Line 4,376 ⟶ 4,507:
{{libheader|Wren-sort}}
{{libheader|Wren-fmt}}
<syntaxhighlight lang="
import "./fmt" for Fmt
var cubesSum = {}
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