[leetcode]939. Minimum Area Rectangle
Analysis
intern intern intern—— [每天刷题并不难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:
主要是set的用法,还有就是新学到了set_intersection(),需要注意的是这个函数不仅仅可以用在set上,也可以用在数组上。另外set中的元素是默认排好序的~
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;
}
};