[leetcode]939. Minimum Area Rectangle

Analysis

intern intern intern—— [每天刷題並不難0.0]

Given a set of points in the xy-plane, determine the minimum area of a rectangle formed from these points, with sides parallel to the x and y axes.
If there isn’t any rectangle, return 0.

explain:

Implement

class Solution {
public:
    int minAreaRect(vector<vector<int>>& points) {
        unordered_map<int, set<int>> p;
        int res = INT_MAX;
        for(auto point:points)
 

            p[point[0]].insert(point[1]);
        for(auto i=p.begin(); i!=p.end(); i++){
            if(i->second.size() < 2)
                continue;
            for(auto j=next(i); j!=p.end(); j++){
                if(j->second.size() < 2)
                    continue;
                vector<
 
int> y;
                set_intersection(begin(i->second), end(i->second), 
                                 begin(j->second), end(j->second), inserter(y, y.begin()));
                for(int k=1; k<y.size(); k++)
                    res = min(res, abs(i->first-j->first)*(y[k]-y[k-1]));
            }
        }
        if(res == INT_MAX)
            return 0;
        return res;
    }
};