Permutations/Derangements: Difference between revisions
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→{{header|Raku}}: Add a version using subfactorials
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(cond ((greaterp from to) '())
(t (cons from (range (add1 from) to)))))
list)▼
'( Examples )
Line 1,518 ⟶ 1,513:
writefln("\n!20 = %s", 20L.subfact);
}</syntaxhighlight>
=={{header|EasyLang}}==
<syntaxhighlight lang=easylang>
global list[] rlist[][] .
proc permlist k . .
if k >= len list[]
for i to len list[]
if i = list[i]
return
.
rlist[][] &= list[]
return
.
for i = k to len list[]
swap list[i] list[k]
permlist k + 1
swap list[k] list[i]
.
.
#
proc derang n . r[][] .
rlist[][] = [ ]
list[] = [ ]
for i to n
list[] &= i
.
permlist 1
r[][] = rlist[][]
.
r[][] = [ ]
derang 4 r[][]
print r[][]
#
func subfac n .
if n < 2
return 1 - n
.
return (subfac (n - 1) + subfac (n - 2)) * (n - 1)
.
#
print "counted / calculated"
for n = 0 to 9
derang n r[][]
print n & ": " & len r[][] & " " & subfac n
.
</syntaxhighlight>
=={{header|EchoLisp}}==
Line 3,797 ⟶ 3,840:
!9 == 133496 == 133496
</pre>
Much faster to just calculate the subfactorial.
<syntaxhighlight lang="raku" line>my @subfactorial = 1,0,{++$ × ($^a + $^b)}…*;
say "!$_: ",@subfactorial[$_] for |^10, 20, 200;</syntaxhighlight>
{{out}}
<pre>!0: 1
!1: 0
!2: 1
!3: 2
!4: 9
!5: 44
!6: 265
!7: 1854
!8: 14833
!9: 133496
!20: 895014631192902121
!200: 290131015521620609254546237518688936375622413566095185632876940298382875066633305125595907908697818551860745708196640009079772455670451355426573609799907339222509103785567575227183775791345718826220455840965346196540544976439608810006794385963854831693077054723298130736781093200499800934036993104223443563872463385599425635345341317933466521378117877578807421014599223577201</pre>
=={{header|REXX}}==
Line 4,127 ⟶ 4,188:
{{libheader|Wren-fmt}}
{{libheader|Wren-big}}
<syntaxhighlight lang="
import "./big" for BigInt
var permute // recursive
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