Hi all !
You can do it in two steps? Find all combinations, then all permutations
of each combination?
perm=: (A.~i.@!@#)
combbit=: 4 : 0
or=. 23 b.
lshift=. 33 b.
lrot=. 32 b.
shift=. 2 ((_2 lrot 2 | [) or _1 lshift ])/\ ]
n=. <:##:_1 (32 b.) 1
l=. >.y%n
p=. y->:i.>:d=.y-x
k=. <"_1(<.p%n)|."0 1((l-1)$0),"1 0 [2 ^&.x: n|p
z=. (d$<(l,0)$0),<(l,1)$0
for. i.x do.
if. l=1 do.
z=. (_1 lshift 1 {. ])&.> z
else.
z=. ((_1 lshift 0 { ]) , [: shift ])&.> z
end.
z=. ,.&.>/\. z
z=. k (or)&.> z
end.
z=. >,.&.>/z
z=. <@:#:"1 z
z=. >,.&.>/z
z
)
sper=: 4 : ',/(perm i.x){"_ 1 (x combbit y)#i.y'
3 sper 4
0 1 2
0 2 1
1 0 2
1 2 0
2 0 1
2 1 0
0 1 3
0 3 1
1 0 3
1 3 0
3 0 1
3 1 0
0 2 3
0 3 2
2 0 3
2 3 0
3 0 2
3 2 0
1 2 3
1 3 2
2 1 3
2 3 1
3 1 2
3 2 1
2 sper 4
0 1
1 0
0 2
2 0
0 3
3 0
1 2
2 1
1 3
3 1
2 3
3 2
1 sper 4
0
1
2
3
Cheers,
Erling Hellenäs
Den 2017-11-20 kl. 08:49, skrev 'Skip Cave' via Programming:
How to find the permutations of y objects taken x at a time?
3 sper 4
0 1 2
0 1 3
0 2 1
0 2 3
0 3 1
0 3 2
1 0 2
1 0 3
1 2 0
1 2 3
1 3 0
1 3 2
2 0 1
2 0 3
2 1 0
2 1 3
2 3 0
2 3 1
3 0 1
3 0 2
3 1 0
3 1 2
3 2 0
3 2 1
2 sper 4
0 1
0 2
0 3
1 0
1 2
1 3
2 0
2 1
2 3
3 0
3 1
3 2
1 sper 4
0
1
2
3
Skip
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