Permutations/Derangements: Difference between revisions
Added Arturo implementation
Drkameleon (talk | contribs) (Added Arturo implementation) |
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9 133496 133496
!20 = 895014631192902121</pre>
=={{header|Arturo}}==
<lang rebol>isClean?: function [s,o][
loop.with:'i s 'a [
if a = o\[i] -> return false
]
return true
]
derangements: function [n][
original: 1..n
select permutate original 'x ->
isClean? x original
]
subfactorial: function [n].memoize[
(n =< 1)? -> 1 - n
-> (n-1) * (add subfactorial n-1 subfactorial n-2)
]
print "Derangements of 1 2 3 4:"
loop derangements 4 'x [
print x
]
print "\nNumber of derangements:"
print [pad "n" 5 pad "counted" 15 pad "calculated" 15]
print repeat "-" 39
loop 0..9 'z [
counted: size derangements z
calculated: subfactorial z
print [pad to :string z 5 pad to :string counted 15 pad to :string calculated 15]
]
print ~"\n!20 = |subfactorial 20|"</lang>
{{out}}
<pre>Derangements of 1 2 3 4:
4 1 2 3
3 1 4 2
3 4 1 2
4 3 1 2
2 1 4 3
2 4 1 3
2 3 4 1
3 4 2 1
4 3 2 1
Number of derangements:
n counted calculated
---------------------------------------
0 1 1
1 0 0
2 1 1
3 2 2
4 9 9
5 44 44
6 265 265
7 1854 1854
8 14833 14833
9 133496 133496
!20 = 895014631192902121</pre>
=={{header|AutoHotkey}}==
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