LeetCode 189. Rotate Array

Given an array, 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]

 

Solution:

class Solution {
    public void rotate(int[] nums, int k) {
        reverseArray(nums);
        reverseSubArray(nums, 0, k % nums.length - 1);
        reverseSubArray(nums, k % nums.length, nums.length - 1);
    }
    
    private void reverseArray(int[] nums) {
        reverseSubArray(nums, 0, nums.length - 1);
    }
    
    private void reverseSubArray(int[] nums, int left, int right) {
        int temp;
        while (left < right) {
            temp = nums[left];
            nums[left] = nums[right];
            nums[right] = temp;
            left++;
            right--;
        }
    }
}