Rotate_Arrray.java

// Given an integer array nums, rotate the array to the right by k steps, where k is non-negative.
// Example 1:

// Input: nums = [1,2,3,4,5,6,7], k = 3
// Output: [5,6,7,1,2,3,4]
// Explanation:
// rotate 1 steps to the right: [7,1,2,3,4,5,6]
// rotate 2 steps to the right: [6,7,1,2,3,4,5]
// rotate 3 steps to the right: [5,6,7,1,2,3,4]
// Example 2:

// Input: nums = [-1,-100,3,99], k = 2
// Output: [3,99,-1,-100]
// Explanation: 
// rotate 1 steps to the right: [99,-1,-100,3]
// rotate 2 steps to the right: [3,99,-1,-100]

class Solution {
    public void rotate(int[] nums, int k) {
        if(nums.length == null || nums.length <=1 || k % nums.length == 0){
            return;
        }

        int n = nums.length;
        k = k % n;

        reverse(nums,0,n-1);
        reverse(nums,0,k-1);
        reverse(nums,k,n-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--;
           }
        }
    }
}