Java Rotate Array K Times

Problem : Given of size ‘n’ and a values ‘k’ around which we need to right rotate the array.

Array: [1,2,3,4,5,6,7], K = 3

• Rorate1: 7,1,2,3,4,5,6
• Rotate2: 6,7,1,2,3,4,5
• Rotate3: 5,6,7,1,2,3,4

Solution Using Reversal:

• This solution uses the reverse function to reverse subarrays of the input array.
• First, the whole array is reversed.
• Then, the first k elements are reversed again.
• Finally, the rest of the elements are reversed again.
• This results in the first k elements moving to the end of the array, which is the desired rotation.

public class RightRotateArray {
	
	public void rotate(int[] nums, int k) {
        k %= nums.length;
        reverse(nums, 0, nums.length - 1);
        reverse(nums, 0, k - 1);
        reverse(nums, k, nums.length - 1);
        
    }
    
    private void reverse(int[] nums, int start, int end) {
        while (start < end) {
            int temp = nums[start];
            nums[start] = nums[end];
            nums[end] = temp;
            start++;
            end--;
        }
    }
    
    public static void main(String[] args) {
    	RightRotateArray rotate = new RightRotateArray();
    	int[] data = {1,2,3,4,5,6,7};
    	rotate.rotate(data, 3);
    	System.out.println(Arrays.toString(data));
	}

}