Re: [Haskell] String permutation

Sukit Tretriluxana wrote:

Dear expert Haskellers,

I am a newbie to Haskell and try to write several algorithms with it. One of them is the string permutation which generates all possible permutations using the characters in the string.

While I could hardly be called an expert haskeller, here's my version: permute :: [a] -> [[a]] permute [] = [[]] permute list = concat $ map (\(x:xs) -> map (x:) (permute xs)) (take (length list) (unfoldr (\x -> Just (x, tail x ++ [head x])) list)) HTH Martin