1828. Queries on Number of Points Inside a Circle

You are given an array points where points[i] = [xi, yi] is the coordinates of the ith point on a 2D plane. Multiple points can have the same coordinates.

You are also given an array queries where queries[j] = [xj, yj, rj] describes a circle centered at (xj, yj) with a radius of rj.

For each query queries[j], compute the number of points inside the jth circle. Points on the border of the circle are considered inside.

Return an array answer, where answer[j] is the answer to the jth query.

class Solution {
public:
    vector<int> countPoints(vector<vector<int>>& points, vector<vector<int>>& queries) {
        vector<int> res;
        for(auto& q : queries) {
            int cx = q[0], cy = q[1], cr = q[2];
            int now = 0;
            for(auto& p : points) {
                int x = p[0], y = p[1];
                int distance = (cx - x) * (cx - x) + (cy - y) * (cy - y);
                if(distance <= cr * cr) now++;
            }
            res.push_back(now);
        }
        return res;
    }
};