6 lines
236 B
Forth
6 lines
236 B
Forth
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let permutations xs =
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let rec insert x = function
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| [] -> [[x]]
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| head :: tail -> (x :: (head :: tail)) :: (List.map (fun l -> head :: l) (insert x tail))
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List.fold (fun s e -> List.collect (insert e) s) [[]] xs
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