Python Program for Reversal algorithm for array rotation

Write a function rotate(arr[], d, n) that rotates arr[] of size n by d elements.

Example :

Input :  arr[] = [1, 2, 3, 4, 5, 6, 7]
         d = 2
Output : arr[] = [3, 4, 5, 6, 7, 1, 2] 

Rotation of the above array by 2 will make array

Python program for reversal algorithm of array rotation    # Function to reverse arr[] from index start to end def rverseArray(arr, start, end):     while (start < end):         temp = arr[start]         arr[start] = arr[end]         arr[end] = temp         start += 1         end = end-1    # Function to left rotate arr[] of size n by d def leftRotate(arr, d):     n = len(arr)     rverseArray(arr, 0, d-1)     rverseArray(arr, d, n-1)     rverseArray(arr, 0, n-1)    # Function to print an array def printArray(arr):     for i in range(0, len(arr)):         print (arr[i])    # Driver function to test above functions arr = [1, 2, 3, 4, 5, 6, 7] leftRotate(arr, 2) # Rotate array by 2 printArray(arr)    # This code is contributed by Devesh Agrawal

Output :

3 4 5 6 7 1 2

Time Complexity : O(n)