Initial data commit

Task/Permutations/Haskell/permutations-5.hs

@@ -0,0 +1,14 @@
+import Data.Bifunctor (second)
+
+permutations :: [a] -> [[a]]
+permutations =
+  let ins x xs n = uncurry (<>) $ second (x :) (splitAt n xs)
+  in foldr
+    ( \x a ->
+        a >>= (fmap . ins x)
+          <*> (enumFromTo 0 . length)
+    )
+    [[]]
+
+main :: IO ()
+main = print $ permutations [1, 2, 3]