BZOJ1218 [HNOI2003]激光炸弹

 1 #include <cstdio>
 2 #include <cmath>
 3 #include <algorithm>
 4 
 5 using namespace std;
 6 
 7 int a[5005][5005];
 8 
 9 int main(){
10     int n, R, x, y, c, i, j, ans = 0, maxc = 5002;
11     scanf("%d%d", &n ,&R);
12     while (n--){
13         scanf("%d%d%d", &x, &y, &c);
14         a[x + 1][y + 1] = c;
15     }
16     for (int i = 1; i < maxc; ++i)
17         for (int j = 1; j < maxc; ++j)
18             a[i][j] += a[i - 1][j] + a[i][j - 1] - a[i - 1][j - 1];
19     maxc -= R;
20     for (int i = 0; i < maxc; ++i)
21         for (int j = 0; j < maxc; ++j)
22             ans = max(ans, a[i + R][j + R] + a[i][j] - a[i + R][j] - a[i][j + R]);
23     printf("%d\n", ans);        
24     return 0;    
25 }