Leetcode 189. Rotate Array

文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

2. Solution

• Version 1

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

• Version 2

class Solution {
public:
    void rotate(vector<int>& nums, int k) {
        int n = nums.size();
        int start = n - k % n;
        int remainder = k % n;
        vector<int> v(remainder);
        for(int i = 0; i < remainder; i++) {
            v[i] = nums[i + start];
        }
        for(int i = n - 1; i >= remainder; i--) {
            nums[i] = nums[i - remainder];
        }
        for(int i = 0; i < remainder; i++) {
            nums[i] = v[i];
        }
    }
};

• Version 3

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

Reference

1. https://leetcode.com/problems/rotate-array/description/