激光炸弹

 

#include <bits/stdc++.h>
using namespace std;
const int N = 5010;
int g[N][N];
int main() {
    int n, r;
    cin >> n >> r;
    int nn = r, mm = r; //判断边界
    for (int i = 0; i < n; i++) {
        int x, y, w;
        cin >> x >> y >> w;
        x++;
        y++; //前缀和下标从1开始
        nn = max(nn, x);
        mm = max(mm, y);
        g[x][y] += w;
    }
    for (int i = 1; i <= nn; i++) {
        for (int j = 1; j <= mm; j++) {
            g[i][j] += g[i - 1][j] + g[i][j - 1] - g[i - 1][j - 1]; 
        }
    }
    int res = 0;
    //枚举所有边长是r的矩形，枚举(i, j)为其右下角
    for (int i = r; i <= nn; i++) {
        for (int j = r; j <= mm; j++) {
            res = max(res, g[i][j] - g[i - r][j] - g[i][j - r] + g[i - r][j - r]);
        }
    }
    cout << res << endl;
    return 0;
}