UVA - 108 Maximum Sum——思维

搞个竖着的前缀和然后枚举连续的行做尺取就可以了，水题

#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
int n, a[150][150], sum[150][150], b[150], ans;
void solve() {
    int sum = 0;
    for (int l = 1, r = 1; r <= n; r++) {
        sum += b[r];
        while (sum < 0 && l <= r) sum -= b[l++];
        ans = max(ans, sum);
    }
}
int main() {
    while (~scanf("%d", &n)) {
        memset(sum, 0, sizeof(sum));
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                scanf("%d", &a[i][j]);
                sum[i][j] = sum[i-1][j] + a[i][j];
            }
        }
        ans = -INF;
        for (int k = 1; k <= n; k++) {
            for (int s = 1; s+k-1 <= n; s++) {
                int t = s+k-1;
                for (int j = 1; j <= n; j++) {
                    b[j] = sum[t][j] - sum[s-1][j];
                }
                solve();
            }
        }
        printf("%d\n", ans);
    }
    return 0;
}