#Leetcode# 189. Rotate Array

Posted 2021-01-23 丧心病狂工科女

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]

代码：

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        int n = nums.size();
        k %= n;
        vector<int> ans;
        for(int i = n - k; i < n; i ++)
            ans.push_back(nums[i]);
        for(int i = 0; i < n - k; i ++)
            ans.push_back(nums[i]);
        
        nums.clear();
        for(int i = 0; i < ans.size(); i ++)
            nums.push_back(ans[i]);
    }
};