[LeetCode] (medium) 593. Valid Square

https://leetcode.com/problems/valid-square/

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.

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class Solution { public: bool validSquare(vector<int>& p1, vector<int>& p2, vector<int>& p3, vector<int>& p4) { unordered_set<int> S({dist(p1, p2), dist(p1, p3), dist(p1, p4), dist(p2, p3), dist(p2, p4), dist(p3, p4)}); return S.find(0) == S.end() && S.size() == 2; } int dist(vector<int> &p1, vector<int> &p2){ return (p1[0]-p2[0])*(p1[0]-p2[0]) + (p1[1]-p2[1])*(p1[1]-p2[1]); } };