Javascript Program for Reversal algorithm for right rotation of an array
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:
Javascript
<script> // JavaScript program for right rotation of // an array (Reversal Algorithm) /*Function to reverse arr[] from index start to end*/ function reverseArray(arr, start, end){ while (start < end){ let temp = arr[start]; arr[start] = arr[end]; arr[end] = temp; start++; end--; } return arr; } /* Function to right rotate arr[] of size n by d */ function rightRotate(arr, d, n){ arr = reverseArray(arr, 0, n-1); arr = reverseArray(arr, 0, d-1); arr = reverseArray(arr, d, n-1); return arr; } /* function to print an array */ function printArray( arr, size){ for (let i = 0; i < size; i++) document.write( arr[i] + " " ); } // driver code let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; let n = arr.length; let k = 3; arr = rightRotate(arr, k, n); printArray(arr, n); </script> |
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!