Add recursive exponential search python implementation

PYTHON/Algorithms/Searching/exponentialSearch.py

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+# Python implementation of recursive exponential search algorithm.
+# This algorithm takes a sorted array as input and returns the index of a target element.
+# If the element does not exist in the array the algorithm returns -1.
+
+
+def binarySearch( arr, l, r, x):
+	if r >= l:
+		mid = l + ( r-l ) // 2
+
+		# If the element is in the middle of the array
+		if arr[mid] == x:
+			return mid
+
+		# If the element is smaller than the middle value then it must be in the left half
+		if arr[mid] > x:
+			return binarySearch(arr, l, mid - 1, x)
+
+		# Else the element can only be in the right half
+		return binarySearch(arr, mid + 1, r, x)
+
+	# If the element does not exist
+	return -1
+
+# Returns the index of the first occurence of the target element
+def exponentialSearch(arr, n, x):
+	# If the first element is the target element
+	if arr[0] == x:
+		return 0
+
+	# Find the range for binary search
+	i = 1
+	while i < n and arr[i] <= x:
+		i = i * 2
+
+	# Call binary search on the range
+	return binarySearch( arr, i // 2, min(i, n-1), x)
+
+
+# Test Case
+list = input("Enter a list of elements").split()
+target = input("Enter the element to be search")
+n = list.len()
+
+result = exponentialSearch(list, n, target)
+if result == -1:
+	print ("Element not found in the array")
+else:
+	print ("Element is present at index %d" %(result))
+