leetcode189. 轮转数组

class Solution {
public:
    void reverse(vector<int>& nums,int l,int r){
        while(l<r)swap(nums[l++],nums[r--]);
    }
    void rotate(vector<int>& nums, int k) {
        int n=nums.size();
        k=k%n;
        reverse(nums,0,n-k-1);
        reverse(nums,n-k,n-1);
        reverse(nums,0,n-1);
    }
};