Submission

Score: 100

User: Fifaxmb

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.003 second

Submitted On: 2026-05-31 21:17:11

#include<bits/stdc++.h>
using namespace std;
using pii = pair<int,int>;
pii dxy[]  = {{1,0},{-1,0},{0,-1},{0,1}};
int main(){
    ios::sync_with_stdio(0);cin.tie(0);
    int n,m;cin >> n >> m;
    vector<string> v(n);
    queue<pii> q;
    vector<vector<bool>> vis(n,vector<bool> (m,0));
    for(int i =0;i < n;i++) cin >> v[i];
    int ans = 0;
    for(int i =0;i <n;i++){
        for(int j =0;j < m;j++){
            if(v[i][j] == '1' && !vis[i][j]){
                int cnt = 1;
                q.push({i,j});
                vis[i][j]  = 1;
                while(!q.empty()){
                    auto [x,y] = q.front();q.pop();
                    for(int d = 0;d < 4;d++){
                        auto[xx,yy] = dxy[d];
                        xx += x;yy += y;
                        if(xx < 0 || yy < 0 || xx >= n || yy >= m || vis[xx][yy] || !(v[xx][yy] - '0')) continue;
                        cnt ++;
                        q.push({xx,yy});
                        vis[xx][yy] = 1;
                    }
                }
                ans = max(ans,cnt);
            }
        }
    }
    cout << ans;
}