题目

Rotate an array of n elements to the right by k steps.

For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4].

答案

class Solution {
    private void reverse(int[] nums, int left, int right) {
        while(left < right) {
            int t = nums[left];
            nums[left++] = nums[right];
            nums[right--] = t;
        }
    }
    public void rotate(int[] nums, int k) {
        k = k % nums.length;
        if(k == 0) return;

        reverse(nums, 0, nums.length - 1);
        reverse(nums, 0, k - 1);
        reverse(nums, k, nums.length - 1);
    }
}