Skip to content
Related Articles

Related Articles

Python Program for Reversal algorithm for array rotation
  • Difficulty Level : Hard
  • Last Updated : 29 Apr, 2020

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] 

Array

Rotation of the above array by 2 will make array

ArrayRotation1



Recommended: Please solve it on “PRACTICE ” first, before moving on to the solution.




# 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)

Please refer complete article on Reversal algorithm for array rotation for more details!

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up
Recommended Articles
Page :