Java Program For Array Rotation by rotating one-by-one
- At each iteration, shift the elements by one position to the left circularly (i.e., first element becomes the last).
- Perform this operation d times to rotate the elements to the left by d position.
Illustration:
Let us take arr[] = [1, 2, 3, 4, 5, 6, 7], d = 2.
First Step:
=> Rotate to left by one position.
=> arr[] = {2, 3, 4, 5, 6, 7, 1}Second Step:
=> Rotate again to left by one position
=> arr[] = {3, 4, 5, 6, 7, 1, 2}Rotation is done by 2 times.
So the array becomes arr[] = {3, 4, 5, 6, 7, 1, 2}
Step-by-step approach:
- Rotate the array to left by one position. For that do the following:
- Store the first element of the array in a temporary variable.
- Shift the rest of the elements in the original array by one place.
- Update the last index of the array with the temporary variable.
- Repeat the above steps for the number of left rotations required.
Below is the implementation of the above approach:
Java
/*package whatever //do not write package name here */import java.io.*;class GFG { public static void rotate(int arr[], int d, int n) { int p = 1; while (p <= d) { int last = arr[0]; for (int i = 0; i < n - 1; i++) { arr[i] = arr[i + 1]; } arr[n - 1] = last; p++; } for (int i = 0; i < n; i++) { System.out.print(arr[i] + " "); } } public static void main(String[] args) { int arr[] = { 1, 2, 3, 4, 5, 6, 7 }; int N = arr.length; // Rotate 2 times int d = 2; // Function call rotate(arr, d, N); }}// contributed by keerthikarathan123 |
Output
3 4 5 6 7 1 2
Time Complexity: O(N * d)
Auxiliary Space: O(1)
Java Program For Array Rotation
Write a Java Program for a given array of integers arr[] of size N and an integer, the task is to rotate the array elements to the left by d positions.
Examples:
Input:
arr[] = {1, 2, 3, 4, 5, 6, 7}, d = 2
Output: 3 4 5 6 7 1 2Input: arr[] = {3, 4, 5, 6, 7, 1, 2}, d=2
Output: 5 6 7 1 2 3 4
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