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) # |
Output :
3 4 5 6 7 1 2
Time Complexity : O(n)