leetcode 593. Valid Square 正方形的判定 + 统计边长 + 想法不错

短命女 2022-06-03 04:45 167阅读 0赞

Given the coordinates of four points in 2D space, return whether the four points could construct a square.

The coordinate (x,y) of a point is represented by an integer array with two integers.

Example:  
Input: p1 = \[0,0\], p2 = \[1,1\], p3 = \[1,0\], p4 = \[0,1\]  
Output: True  
Note:

All the input integers are in the range \[-10000, 10000\].  
A valid square has four equal sides with positive length and four equal angles (90-degree angles).  
Input points have no order.

本题题意很简单，就是判定是否是正方形，直接统计所有的边长即可

代码如下：

#include <iostream>
    #include <vector>
    #include <map>
    #include <set>
    #include <queue>
    #include <stack>
    #include <string>
    #include <climits>
    #include <algorithm>
    #include <sstream>
    #include <functional>
    #include <bitset>
    #include <numeric>
    #include <cmath>
    
    using namespace std;
    
    
    class Solution 
    {
    public:
        bool validSquare(vector<int>& p1, vector<int>& p2, vector<int>& p3, vector<int>& p4) 
        {
            map<int, int> mmp;
            vector<vector<int>> all{p1,p2,p3,p4};
            for (int i = 0; i < all.size(); i++)
            {
                for (int j = i + 1; j < all.size(); j++)
                {
                    int x1 = all[i][0], y1 = all[i][1], x2 = all[j][0], y2 = all[j][1];
                    int len = (x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2);
                    if (len == 0)
                        return false;
                    mmp[len]++;
                }
            }
    
            return mmp.size() == 2;
        }
    };