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math.combinatorics: adding all-combinations? and all-permutations?.

db4
John Benediktsson 2013-10-01 20:44:57 -07:00
parent bd55cd3074
commit d76f8d151d
1 changed files with 8 additions and 1 deletions
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9
basis/math/combinatorics/combinatorics.factor
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@ -4,7 +4,7 @@
USING: accessors arrays assocs binary-search classes.tuple
combinators fry hints kernel kernel.private locals math
math.order math.ranges memoize namespaces sequences
sequences.private sorting strings ;
sequences.private sorting strings vectors ;
FROM: sequences => change-nth ;
IN: math.combinatorics
@ -17,6 +17,7 @@ IN: math.combinatorics
GENERIC: nths-unsafe ( indices seq -- seq' )
M: string nths-unsafe (nths-unsafe) ;
M: array nths-unsafe (nths-unsafe) ;
M: vector nths-unsafe (nths-unsafe) ;
M: iota-tuple nths-unsafe (nths-unsafe) ;
M: object nths-unsafe (nths-unsafe) ;
@ -118,6 +119,9 @@ PRIVATE>
: all-permutations ( seq -- seq' )
[ ] map-permutations ;
: all-permutations? ( ... seq quot: ( ... elt -- ... ? ) -- ... ? )
permutations-quot all? ; inline
: find-permutation ( ... seq quot: ( ... elt -- ... ? ) -- ... elt/f )
[ permutations-quot find drop ]
[ drop over [ permutation ] [ 2drop f ] if ] 2bi ; inline
@ -235,6 +239,9 @@ PRIVATE>
: all-combinations ( seq k -- seq' )
[ ] map-combinations ;
: all-combinations? ( ... seq k quot: ( ... elt -- ... ? ) -- ... ? )
combinations-quot all? ; inline
: find-combination ( ... seq k quot: ( ... elt -- ... ? ) -- ... elt/f )
[ combinations-quot find drop ]
[ drop pick [ combination ] [ 3drop f ] if ] 3bi ; inline