Here we will see how to rotate an array to left direction based on the user input shifts.

Sample Input:
Array Size: 5
Shifts Count: 3
Array: 1 2 3 4 5
Output:  4 5 1 2 3

Rotate an Array to Left direction:

Approach:

  • Looping the array for ‘n’ times.
  • For each time it is getting the first element from the array and stores it into a variable (firstElement).
  • Again iterating the array from 0 to length-1 times and replacing the same array values with i+1 (a[i]=a[i+1])
  • Finally, add the firstElement to the end of the array (arr[arr.length-1]=firstElement).
Solution:
import java.util.Scanner;
public class ArrayLeftRotation {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter the size of the Array: ");
        int size = scan.nextInt();
        System.out.println("Enter the shifts you want to move: ");
        int shifts = scan.nextInt();
        int[] array = new int[size];
        System.out.println("Enter "+size+" elements:");
        for (int i=0; i<size; ++i) {
            array[i] = scan.nextInt();
        }
        for (int i=0; i<shifts; ++i) {
            rotateArray(array);
        }
        for (int a : array) {
            System.out.print(a+" ");
        }
    }

    public static void rotateArray(int[] arr){
        int firstElement = arr[0];
        for(int i=0;i<arr.length-1;i++){
            arr[i]=arr[i+1];
        }
        arr[arr.length-1]=firstElement;
    }
}
Output:
Enter the size of the Array: 
5
Enter the shifts you want to move: 
3
Enter 5 elements:
1 2 3 4 5
Output: 
4 5 1 2 3

Happy Learning 🙂

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