题目大意：给出一个三位矩阵，求说子矩阵和最大值。
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 <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;
typedef long long ll;
const int N = 30;
const ll INF = 0x3f3f3f3f3f3f3f;
int x, y, z;
ll g[N][N][N], s[N][N][N];
void init() {
memset(s, 0, sizeof(s));
scanf("%d%d%d", &x, &y, &z);
for (int i = 1; i <= x; i++) {
for (int j = 1; j <= y; j++) {
for (int k = 1; k <= z; k++) {
scanf("%lld", &g[i][j][k]);
s[j][k][i] = s[j][k-1][i] + s[j-1][k][i] - s[j-1][k-1][i] + g[i][j][k];
}
}
}
}
ll count(int n, int m, int p, int q, int x) {
return s[m][q][x] - s[n][q][x] - s[m][p][x] + s[n][p][x];
}
ll solve() {
ll ans = -INF, dp[N];
for (int n = 1; n <= y; n++) {
for (int m = n; m <= y; m++) {
for (int p = 1; p <= z; p++) {
for (int q = p; q <= z; q++) {
memset(dp, 0, sizeof(dp));
for (int i = 1; i <= x; i++) {
ll t = count(n-1, m, p-1, q, i);
dp[i] = max(dp[i-1] + t, t);
ans = max(dp[i], ans);
}
}
}
}
}
return ans;
}
int main() {
int cas;
scanf("%d", &cas);
while (cas--) {
init();
printf("%lld\n", solve());
if (cas) printf("\n");
}
return 0;
}