Data commit

Task/Quickselect-algorithm/Haskell/quickselect-algorithm.hs

@@ -0,0 +1,18 @@
+import Data.List (partition)
+
+quickselect
+  :: Ord a
+  => [a] -> Int -> a
+quickselect (x:xs) k
+  | k < l = quickselect ys k
+  | k > l = quickselect zs (k - l - 1)
+  | otherwise = x
+  where
+    (ys, zs) = partition (< x) xs
+    l = length ys
+
+main :: IO ()
+main =
+  print
+    ((fmap . quickselect) <*> zipWith const [0 ..] $
+     [9, 8, 7, 6, 5, 0, 1, 2, 3, 4])