Bzoj1218 [hnoi2003] laser bomb

After the question is written, it should be DP ..

It was originally a scanning line + line segment tree, but it was still possible to squeeze 5000 ^ 2, so the brute force enumeration square + so-called DP was solved.

 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 }

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Bzoj1218 [hnoi2003] laser bomb