PROG-T1077: Key

#include <iostream>
using namespace std;

int qsum[1010][1010];
int np, nh;

int main(){

    int x, y, r, x1, y1, x2, y2;

    scanf("%d %d", &np, &nh);
    for(int i = 0; i < np; ++i){
        scanf("%d %d", &x, &y);
        ++qsum[x + 1][y + 1];
    }

    /// Quick Sum
    for(int i = 1; i <= 1001; ++i){
        for(int j = 1; j <= 1001; ++j){
            qsum[i][j] = qsum[i][j - 1] + qsum[i - 1][j] - qsum[i - 1][j - 1] + qsum[i][j];
        }
    }

    for(int i = 0; i < nh; ++i){
        scanf("%d %d %d", &x, &y, &r);
        ++x;
        ++y;
        x1 = (x - r > 0) ? x - r : 1;
        y1 = (y - r > 0) ? y - r : 1;
        x2 = (x + r <= 1001) ? x + r : 1001;
        y2 = (y + r <= 1001) ? y + r : 1001;
        cout << qsum[x2][y2] - qsum[x1 - 1][y2] - qsum[x2][y1 - 1] + qsum[x1 - 1][y1 - 1] << "\n";
    }

    return 0;
}