求助大劳（能者多劳）

#include <bits/stdc++.h>
using namespace std;
int n, a[125][125], v[125][125], maxn = -0x3f3f3f3f;
int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			cin >> a[i][j];
			if (i == 1 && j == 1) {
				v[i][j] = a[i][j];
			} else if (i == 1) {
				v[i][j] = a[i][j] + v[i][j - 1];
			} else if (j == 1) {
				v[i][j] = a[i][j] + v[i - 1][j];
			} else {
				v[i][j] = a[i][j] + v[i - 1][j] + v[i][j - 1] - v[i - 1][j - 1];
			}
		}
	}
	for (int t = 1; t <= n; t++) {
		for (int i = t; i <= n ; i++) {
			for (int j = t; j <= n; j++) {
				maxn = max(maxn, v[i][j] - v[i - t][j] - v[i][j - t] + v[i - t][j - t]);
			}
		}
	}
	cout << maxn;
	return 0;
}