Merge pull request #749 from thesmitpatel/patch-2

Create binary_search.py

Python-programming-1/binary_search.py

@@ -0,0 +1,39 @@
+# Python 3 program for recursive binary search. 
+# Modifications needed for the older Python 2 are found in comments. 
+
+# Returns index of x in arr if present, else -1 
+def binary_search(arr, low, high, x): 
+
+    # Check base case 
+    if high >= low: 
+
+        mid = (high + low) // 2
+
+        # If element is present at the middle itself 
+        if arr[mid] == x: 
+            return mid 
+
+        # If element is smaller than mid, then it can only 
+        # be present in left subarray 
+        elif arr[mid] > x: 
+            return binary_search(arr, low, mid - 1, x) 
+
+        # Else the element can only be present in right subarray 
+        else: 
+            return binary_search(arr, mid + 1, high, x) 
+
+    else: 
+        # Element is not present in the array 
+        return -1
+
+# Test array 
+arr = [ 2, 3, 4, 10, 40 ] 
+x = 10
+
+# Function call 
+result = binary_search(arr, 0, len(arr)-1, x) 
+
+if result != -1: 
+    print("Element is present at index", str(result)) 
+else: 
+    print("Element is not present in array")