all tasks

Task/Sorting-algorithms-Radix-sort/Haskell/sorting-algorithms-radix-sort.hs

@@ -0,0 +1,22 @@
+import Data.Bits (Bits(testBit, bitSize))
+import Data.List (partition)
+
+lsdSort :: (Ord a, Bits a) => [a] -> [a]
+lsdSort = fixSort positiveLsdSort
+
+msdSort :: (Ord a, Bits a) => [a] -> [a]
+msdSort = fixSort positiveMsdSort
+
+-- Fix a sort that puts negative numbers at the end, like positiveLsdSort and positiveMsdSort
+fixSort sorter list = uncurry (flip (++)) (break (< 0) (sorter list))
+
+positiveLsdSort :: (Bits a) => [a] -> [a]
+positiveLsdSort list = foldl step list [0..bitSize (head list)] where
+	step list bit = uncurry (++) (partition (not . flip testBit bit) list)
+
+positiveMsdSort :: (Bits a) => [a] -> [a]
+positiveMsdSort list = aux (bitSize (head list) - 1) list where
+	aux _ [] = []
+	aux (-1) list = list
+	aux bit list = aux (bit - 1) lower ++ aux (bit - 1) upper where
+		(lower, upper) = partition (not . flip testBit bit) list