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hokamoto/grape_puzzle.hs

Last active January 1, 2016 09:19
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grape_puzzle.hs
import Data.List
-- http://d.hatena.ne.jp/guccyon/20090510/p1
combn [] n=[]
combn lst 1=map (\x -> [x]) lst
combn (x:xs) n=[x:y| y <- combn xs (n-1)] ++ combn xs n
ss = combn [1..10] 4
ans = [s | sp <- ss, s <- (permutations sp), let x1 = abs(s !! 0 - s !! 1); x2 = abs(s !! 1 - s !! 2); x3 = abs(s !! 2 - s !! 3); x4 = abs(x1 - x2); x5 = abs(x2 - x3); x6 = abs(x4 - x5) in length (nub (x1:x2:x3:x4:x5:x6:s)) == 10]
main = print ans
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