new files

Task/Binary-search/Haskell/binary-search-1.hs

@@ -0,0 +1,9 @@
+binarySearch :: Integral a => (a -> Ordering) -> (a, a) -> Maybe a
+binarySearch p (low,high)
+  | high < low = Nothing
+  | otherwise =
+      let mid = (low + high) `div` 2 in
+      case p mid of
+        LT -> binarySearch p (low, mid-1)
+        GT -> binarySearch p (mid+1, high)
+        EQ -> Just mid

Task/Binary-search/Haskell/binary-search-2.hs

@@ -0,0 +1,5 @@
+import Data.Array
+
+binarySearchArray :: (Ix i, Integral i, Ord e) => Array i e -> e -> Maybe i
+binarySearchArray a x = binarySearch p (bounds a) where
+  p m = x `compare` (a ! m)