1610. 可见点的最大数目

 1 class Solution {
 2 public:
 3     const double pi=M_PI;
 4     double get_angel(int x1,int y1,int x2,int y2)
 5     {
 6         return atan(1.0*(y2-y1)/(x2-x1))*180/pi;
 7     }
 8     int visiblePoints(vector<vector<int>>& points, int angle, vector<int>& location) {
 9         set<double>s;
10         vector<double>a;
11         int ans=0,mx=0;
12         for(auto &p:points)
13         {
14             double tmp;
15             if(p[0]==location[0]&&p[1]==location[1])
16             {
17                 ans++;
18                 continue;
19             }
20             if(location[0]==p[0])
21             {
22                 if(location[1]<p[1])tmp=90.0;
23                 else tmp=-90.0;
24             }
25             else
26             {
27                   tmp=get_angel(location[0],location[1],p[0],p[1]);
28                   if(location[1]<p[1]&&tmp<0)tmp+=180;
29                   else if(location[1]>p[1]&&tmp>0)tmp-=180;
30                   else if(location[1]==p[1]&&location[0]>p[0])tmp=180;
31             }
32             a.push_back(tmp); 
33             a.push_back(tmp+360);
34         }
35         sort(a.begin(),a.end());
36         for(auto &p:a)
37         {
38             int t=upper_bound(a.begin(),a.end(),p+angle)-lower_bound(a.begin(),a.end(),p);
39             mx=max(t,mx);
40         }
41         return ans+mx;
42     }
43 };