Rotate Array

Given an array, rotate the array to the right by k steps, where k is non-negative.

Follow up:

• Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.

• Could you do it in-place with O(1) extra space?

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]

Constraints:

• 1 <= nums.length <= 2 * 10^4

• It's guaranteed that nums[i] fits in a 32 bit-signed integer.

• k >= 0

class Solution {
    public void swap(int[] nums, int i, int j) {
        int temp = nums[i];
        nums[i] = nums[j];
        nums[j] = temp;
    }

    public void rotate(int[] nums, int k) {
        k = k % nums.length;
        int i = 0, j = nums.length - k - 1;
        while (i < j)
            swap(nums, i++, j--);
        i = nums.length - k;
        j = nums.length - 1;
        while (i < j)
            swap(nums, i++, j--);
        i = 0;
        j = nums.length - 1;
        while (i < j)
            swap(nums, i++, j--);
    }
}