UVA-10755 Garbage Heap 三维子矩阵最大和

#include <cstdlib>
#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
typedef long long LL;

const LL INF = 1LL<<60;
int A, B, C;
LL sumz[25][25][25]; // 平面上[1,1]到[i][j]在高度为k时的区域前缀和

LL get(int x1, int y1, int x2, int y2, int z) {
return sumz[x2][y2][z] - sumz[x1-1][y2][z] - sumz[x2][y1-1][z] + sumz[x1-1][y1-1][z];
}

void solve() {
// 需要枚举平面上的二维组合
LL ret = -INF;
LL Min, s;
for (int i = 1; i <= A; ++i) {
for (int j = i; j <= A; ++j) {
for (int k = 1; k <= B; ++k) {
for (int h = k; h <= B; ++h) {
Min = 0;
for (int p = 1; p <= C; ++p) {
s = get(i, k, j, h, p);
ret = max(ret, s - Min);
if (s < Min) Min = s;
}
}
}
}
}
printf("%lld\n", ret);
}

int main() {
int T;
scanf("%d", &T);
while (T--) {
scanf("%d %d %d", &A, &B, &C);
LL tot, x;
for (int i = 1; i <= A; ++i) {
for (int j = 1; j <= B; ++j) {
tot = 0;
for (int k = 1; k <= C; ++k) {
scanf("%lld", &x);
tot += x;
sumz[i][j][k] = sumz[i-1][j][k] + sumz[i][j-1][k] - sumz[i-1][j-1][k] + tot;
}
}
}
solve();
if (T) puts("");
}
return 0;
}