29 lines
1.1 KiB
Factor
29 lines
1.1 KiB
Factor
USING: kernel
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combinators.short-circuit
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math math.combinatorics math.ranges
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sequences
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qw prettyprint ;
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IN: rosetta.dinesman
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: /= ( x y -- ? ) = not ;
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: fifth ( seq -- elt ) 4 swap nth ;
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: meets-constraints? ( seq -- ? )
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{
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[ first 5 /= ] ! Baker does not live on the top floor.
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[ second 1 /= ] ! Cooper does not live on the bottom floor.
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[ third { 1 5 } member? not ] ! Fletcher does not live on either the top or bottom floor.
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[ [ fourth ] [ second ] bi > ] ! Miller lives on a higher floor than does Cooper.
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[ [ fifth ] [ third ] bi - abs 1 /= ] ! Smith does not live on a floor adjacent to Fletcher's.
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[ [ third ] [ second ] bi - abs 1 /= ] ! Fletcher does not live on a floor adjacent to Cooper's.
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} 1&& ;
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: solutions ( -- seq )
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5 [1,b] all-permutations [ meets-constraints? ] filter ;
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: >names ( seq -- seq )
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[ qw{ baker cooper fletcher miller smith } nth swap 2array ] map-index ;
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: dinesman ( -- )
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solutions [ >names . ] each ;
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