悬线法

#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define met(a, b) memset(a, b, sizeof(a))
#define rep(i, a, b) for(int i = a; i <= b; i++)
#define bep(i, a, b) for(int i = a; i >= b; i--)
#define pb push_back
#define mp make_pair
#define debug cout << "KKK" << endl
#define ls num*2
#define rs num*2+1
#define re return
using namespace std;
const ll mod = 998244353;
const double PI = acos(-1);
const ll INF = 2e18+1;
const int inf = 1e9 + 15;
const double eps = 1e-7;
const int maxn = 2e3 + 5;
int l[maxn][maxn], r[maxn][maxn], up[maxn][maxn];
int ma[maxn][maxn];
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);    cout.tie(0);
    int n, m; cin >> n >> m;
    rep(i, 1, n){
        rep(j, 1, m){
            cin >> ma[i][j];
            l[i][j] = r[i][j] = j;
            up[i][j] = 1;
        }
    }
    rep(i, 1, n){
        rep(j, 2, m) if(ma[i][j] + ma[i][j-1] == 1) l[i][j] = l[i][j-1];
        bep(j, m-1, 1) if(ma[i][j] + ma[i][j+1] == 1) r[i][j] = r[i][j+1];
    }
    int ans1 = 0, ans2 = 0;
    rep(i, 1, n){
        rep(j, 1, m){
            if(i > 1 && ma[i][j] + ma[i-1][j] == 1){
                up[i][j] = up[i-1][j] + 1;
                l[i][j] = max(l[i-1][j], l[i][j]);  // 因为是左边能到达的坐标，max越大表示离i越近
                r[i][j] = min(r[i-1][j], r[i][j]);  // 同上，min越小表示离i越近。
            }
            int x = r[i][j] - l[i][j] + 1;
            int y = min(x, up[i][j]);
            ans1 = max(ans1, y*y);
            ans2 = max(ans2, x*up[i][j]);
        }
    }
    cout << ans1 << ‘\n‘ << ans2 << endl;
    re 0;
}