Submission

Score: 100

User: august

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.004 second

Submitted On: 2026-03-18 19:52:05

#include <bits/stdc++.h>
using namespace std;

#define int long long


int32_t main() {
    cin.tie(0)->sync_with_stdio(0);
    int n,m;
    cin>> n>> m;

    vector<string> s(n);
    for (int i=0; i<n; i++) cin>> s[i];

    int ans = 0;
    int di[4] = {-1, 0, 1, 0}, dj[4] = {0, 1, 0, -1};

    for (int i=0; i<n; i++) {
        for (int j=0; j<m; j++) {
            if (s[i][j] == '1') {
                s[i][j] = '0';
                queue<pair<int,int>> q;
                q.push({i,j});

                int cnt=1;
                while (!q.empty()) {
                    int ci=q.front().first, cj=q.front().second;
                    q.pop();

                    for (int e=0; e<4; e++) {
                        int ni=ci+di[e], nj=cj+dj[e];
                        if (ni<0 || nj<0 || ni>=n || nj>=m || s[ni][nj] == '0') continue;
                        s[ni][nj] = '0';
                        cnt++;
                        q.push({ni,nj});
                    }
                }
                ans = max(ans, cnt);
            }
        }
    }
    cout<< ans;
}