593.valid-square.cpp

/*
 * @lc app=leetcode id=593 lang=cpp
 *
 * [593] Valid Square
 *
 * https://leetcode.com/problems/valid-square/description/
 *
 * algorithms
 * Medium (40.76%)
 * Total Accepted:    20.5K
 * Total Submissions: 50.2K
 * Testcase Example:  '[0,0]\n[1,1]\n[1,0]\n[0,1]'
 *
 * 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.
 * 
 * 
 * 
 * 
 */

class Solution {
public:
//     bool checkSame(vector<int>& p1, vector<int>& p2, vector<int>& p3){
//         return pow((p1[0] - p2[0]),2)+ pow((p1[1] - p2[1]),2) == pow((p1[0] - p3[0]),2) + pow((p1[1] - p3[1]),2);
//     }
    int llen(vector<int>& p1, vector<int>& p2){
        return pow((p1[0] - p2[0]),2)+ pow((p1[1] - p2[1]),2);
    }
    bool callme(vector<int>& p1, vector<int>& p2, vector<int>& p3, vector<int>& p4){
        int x = llen(p1, p2);
        cout<<x<<":"<<llen(p2, p4)<<" "<<llen(p3, p4)<<" "<<llen(p1, p3);
        if(x!=0 && x*2 == llen(p1, p4) && x == llen(p2, p4) && x == llen(p3, p4) && x == llen(p1, p3))
            return true;
        return false;
    }
    static bool comp(const vector<int> &p1, const vector<int> &p2){
        if(p1[0] == p2[0])
            return p1[1] < p2[1];
        return p1[0] < p2[0];
    }
    bool validSquare(vector<int>& p1, vector<int>& p2, vector<int>& p3, vector<int>& p4) {
        vector<vector<int>> mm{p1, p2, p3, p4};
        sort(mm.begin(), mm.end(), comp); // now (p1-p4) and (p3-p2) are diag
        for(auto e: mm)
            cout<<e[0]<<":"<<e[1]<<"\n";
        // if(checkSame(p1, p2, p3)){
        return callme(mm[0], mm[1], mm[2], mm[3]);
        // }else if(checkSame(p1, p2, p4)){
        //     return callme(p1, p2, p4, p3);
        // }else if(checkSame(p1, p3, p4)){
        //     return callme(p1, p3, p4, p2);
        // }else
        //     return false;
    }
};