感觉是对的

#include<bits/stdc++.h>
#define N 1001
#define io ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
int s[N][N];
int n, m, y = 0;
int main() {
	io
	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		string ss;
		cin >> ss;
		for (int j = 1; j <= m; j++) {
			s[i][j] = s[i - 1][j] + s[i][j - 1]\
			          - s[i - 1][j - 1]\
			          +(ss[j] - '0');
		}
	}
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++) {
			if (s[i][j] == i * j / 2){ y = max(y, i * j);
            cout<<i<<' '<<j<<"\n";}
		}
	cout << y;
	return 0;
}