LeetCode：Rotate Array（旋转数组）

题目

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

Example 1:

Input: [1,2,3,4,5,6,7] and 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: [-1,-100,3,99] and 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]

Note:
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?

思路

偷懒只做了一种方法：直接从尾部取元素插到头部，反复迭代k次完成要求。效率较低。

代码

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        int n=nums.size();
        if(!(k=k%n))
            return;
        int temp;
        for(int i=0;i<k;i++)
        {
            nums.insert(nums.begin(),1,nums.back());
            nums.erase(nums.end()-1);
        }
    }
};