解题思路

依题意枚举，再利用前缀和优化即可。

code

# include <bits/stdc++.h>
using namespace std;
int n, dp[110], a[110][110], t, ret = INT_MIN;
int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			scanf("%d", &a[i][j]);
		}
	}
	for (int k = 1; k <= n; k++) {
		memset(dp, 0, sizeof(dp));
		for (int i = k; i <= n; i++) {
			t = 0;
			for (int j = 1; j <= n; j++) {
				dp[j] += a[i][j];
				t = max(0, t) + dp[j];
				ret = max(ret, t);
			}
		}
	}
	cout << ret;
	return 0;
}