Given an array, right rotate it by k elements.
After K=3 rotation
Examples:
Input: arr[] = {1, 2, 3, 4, 5,
6, 7, 8, 9, 10}
k = 3
Output: 8 9 10 1 2 3 4 5 6 7
Input: arr[] = {121, 232, 33, 43 ,5}
k = 2
Output: 43 5 121 232 33
Note : In the below solution, k is assumed to be smaller than or equal to n. We can easily modify the solutions to handle larger k values by doing k = k % n
Algorithm:
rotate(arr[], d, n) reverseArray(arr[], 0, n-1) ; reverse(arr[], 0, d-1); reverse(arr[], d, n-1);
Below is the implementation of above approach:
Python3
# Python3 program for right rotation of # an array (Reversal Algorithm)# Function to reverse arr# from index start to enddef reverseArray( arr, start, end): while (start < end): arr[start], arr[end] = arr[end], arr[start] start = start + 1 end = end - 1 # Function to right rotate arr# of size n by d def rightRotate( arr, d, n): reverseArray(arr, 0, n - 1); reverseArray(arr, 0, d - 1); reverseArray(arr, d, n - 1);# function to print an array def printArray( arr, size): for i in range(0, size): print (arr[i], end = ' ')# Driver codearr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]n = len(arr)k = 3 # Function callrightRotate(arr, k, n)printArray(arr, n)# This article is contributed # by saloni1297 |
Output:
8 9 10 1 2 3 4 5 6 7
Time Complexity: O(N)
Auxiliary Space: O(1)
Please refer complete article on Reversal algorithm for right rotation of an array for more details!
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