Submission

Score: 100

User: poni

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.004 second

Submitted On: 2026-10-08 13:44:59

#include <bits/stdc++.h>

using namespace std;
#define int long long

signed main() {
    cin.tie(0)->sync_with_stdio(0);

    int m, n;
    cin >> m >> n;

    bool a[m][n];
    for (int i = 0; i < m; i++) {
        string s;
        cin >> s;
        for (int j = 0; j < n; j++) a[i][j] = (s[j] == '1');
    }

    pair<int, int> dir[4] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
    int mx = 0;
    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            if (!a[i][j]) continue;
            int cur = 0;

            queue<pair<int, int>> q;
            q.push({i, j});
            a[i][j] = 0;
            while (!q.empty()) {
                auto [ci, cj] = q.front();
                q.pop();
                cur++;
                for (auto [di, dj] : dir) {
                    int ni = ci+di, nj = cj+dj;
                    if (ni < 0 || nj < 0 || ni >= m || nj >= n) continue;
                    if (!a[ni][nj]) continue;
                    a[ni][nj] = 0;
                    q.push({ni, nj});
                }
            }
            mx = max(mx, cur);
        }
    }
    cout << mx;
}