Leetcode 189 Rotate Array

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].

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

数组移位，额外要求只能使用O(1) 的空间复杂度。

本质等于最后k个需要移到前面，将最后k个和其余部分先全部逆置，再将整个数组逆置就行了，画个图就能证明出来。

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        k = k % nums.size();
        reverse(nums.begin(), nums.begin()+nums.size()-k);
        reverse(nums.begin()+nums.size()-k, nums.begin()+nums.size());
        reverse(nums.begin(), nums.begin()+nums.size());
    }
};