Update Binary_search.py

Iterative approach take time. And time complexity is high. Instead of using this approach we can use recursive approach.

Author: tanujdhiman

Binary_search.py

@@ -1,23 +1,23 @@
 # It returns location of x in given array arr  
 # if present, else returns -1 
 def binarySearch(arr, l, r, x):
-    while l <= r:
-
-        mid = l + (r - l) / 2 #extracting the middle element from the array
-        mid=int(mid) #it has to be integer
-
-        # Check if x is present at mid 
+    if l <= r:
+        
+        mid = (l+r) // 2 #extracting the middle element from the array
+        
+        # If element is present at the middle itself
         if arr[mid] == x:
             return mid
-
-            # If x is greater, ignore left half
-        elif arr[mid] < x:
-            l = mid + 1 #l is initialised to the rightmost element of the middle so that the search could be started from there the next time
-
-        # If x is smaller, ignore right half 
-        elif x<arr[mid]:
-            r = mid - 1 #r is initialised to the leftmost element of the middle so that the search goes till there only the next time
-
+        
+        # If element is smaller than mid, then it can only
+        # be present in left subarray
+        elif arr[mid] > x:
+            return binary_search(arr, l, mid - 1, x)
+ 
+        # Else the element can only be present in right subarray
+        else:
+            return binary_search(arr, mid + 1, r, x)
+            
     # If we reach here, then the element was not present 
     return -1