UVA - 10755 Garbage Heap

题目大意：给出一个三维矩阵，求子矩阵和最大值。

解题思路：现将各个平面上的矩阵记录下矩阵和，然后可以枚举二维上的矩阵，映射成三维去做。

#include <cstdio>
#include <algorithm>
using namespace std;

int main() {
    int T;
    scanf("%d", &T);
    while (T--) {
        int A, B, C; 
        long long tmp, s[25][25][25] = {0};
        scanf("%d%d%d", &A, &B, &C);
        for (int i = 1; i <= A; i++)
            for (int j = 1; j <= B; j++)
                for (int k = 1; k <= C; k++) {
                    scanf("%lld", &tmp);
                    s[i][j][k] = s[i][j][k-1] + s[i][j-1][k] - s[i][j-1][k-1] + tmp;
                }

        long long ans = -0x3f3f3f3f3f3f3f;
        for (int m = 1; m <= B; m++)
            for (int n = m; n <= B; n++)
                for (int p = 1; p <= C; p++)
                    for (int q = p; q <= C; q++) {
                        long long MAX = 0;
                        for (int x = 1; x <= A; x++) {
                            long long sum = s[x][n][q] - s[x][m-1][q] - s[x][n][p-1] + s[x][m-1][p-1];
                            MAX = max(MAX + sum, sum);
                            ans = max(ans, MAX);
                        }
                    }
        printf("%lld\n", ans);
        if (T) printf("\n");
    }
    return 0;
}