Description

Submission

class Solution {
public:
    int visiblePoints(vector<vector<int>>& points, int angle, vector<int>& location) {
        vector<double> angles;
        int same = 0;
        const double pi = 3.1415926;
        for(auto p : points) {
            double dx = p[0] - location[0];
            double dy = p[1] - location[1]; 

            if(dx == 0 && dy == 0) {
                same++;
                continue;
            }
            double alpha = atan2(dy, dx);
            angles.push_back(alpha);
            
        }

        sort(angles.begin(), angles.end());
        int n = angles.size();
        for(int i = 0; i < n; ++i) {
            angles.push_back(angles[i]+2*pi);
        }

        int ret = 0;
        for(int i = 0, j = 0; i < angles.size(); ++i) {
            while(j < 2 * n && angles[j] - angles[i] < angle * 1.0 * pi / 180 + 0.00000000001)
                j++;
            ret = max(ret, j - i);
        }

        return ret + same;
    }
};