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jvvk/fogcreek_hash.hs

Created August 19, 2014 12:50
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Fogcreek hash problem
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fogcreek_hash.hs
hash s h0 str = last $ scanl1 (\x y -> x*37 + y) (h0:[fromJust $ elemIndex c str | c <- s])
unhash h h0 str = reverse $ unfoldr (\x -> if x == h0 then Nothing else Just (str !! (x `mod` 37), x `quot` 37)) h
hash "leepadg" 7 "acdegilmnoprstuw"
unhash 680131659347 7 "acdegilmnoprstuw"
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