all tasks

Task/Sorting-algorithms-Merge-sort/Standard-ML/sorting-algorithms-merge-sort.ml

@@ -0,0 +1,16 @@
+fun merge cmp ([], ys) = ys
+  | merge cmp (xs, []) = xs
+  | merge cmp (xs as x::xs', ys as y::ys') =
+      case cmp (x, y) of GREATER => y :: merge cmp (xs, ys')
+                       | _       => x :: merge cmp (xs', ys)
+;
+fun merge_sort cmp [] = []
+  | merge_sort cmp [x] = [x]
+  | merge_sort cmp xs = let
+      val ys = List.take (xs, length xs div 2)
+      val zs = List.drop (xs, length xs div 2)
+    in
+      merge cmp (merge_sort cmp ys, merge_sort cmp zs)
+    end
+;
+merge_sort Int.compare [8,6,4,2,1,3,5,7,9]