Initial Commit

binary.exs

@@ -0,0 +1,25 @@
+defmodule BinarySearch do
+  def binary_search(_numbers, _key, low, high) when low > high do
+    :not_found
+  end
+
+  @spec binary_search(list, integer, integer, integer) :: integer | :not_found
+  def binary_search(numbers, key, low, high) do
+    md = low + Integer.floor_div(high-low, 2)
+    IO.inspect(md)
+    case elem(numbers, md) do
+      x when x > key -> binary_search(numbers, key, low, md-1)
+      x when x < key -> binary_search(numbers, key, md+1, high)
+      x when x == key -> md
+    end
+  end
+
+  @spec search(tuple, integer) :: {:ok, integer} | :not_found
+  def search(numbers, key) do
+    case binary_search(numbers, key, 0, tuple_size(numbers)-1) do
+      :not_found -> :not_found
+      x -> {:ok, x}
+    end
+  end
+end
+