Submission

Score: 100

User: C12

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.005 second

Submitted On: 2026-01-04 12:53:49

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

#define f first
#define s second
#define pii pair<ll,ll>
#define puii pair<ull,ull>
#define piii pair<ll,pii>
#define ll long long
#define ull unsigned long long
#define mp make_pair
 
#define mpiii(a,b,c) make_pair(a,make_pair(b,c));
// ll mod = 1000000007;

ll x,y,nx,ny;
ll n,m;
int board[171][171];
ll cnt;
ll mx = 0;
queue<pii>q;

int posx[4] = {-1,1,0,0};
int posy[4] = {0,0,-1,1};

void dfs(){
    cnt = 0;
    while(!q.empty()){
        x = q.front().f;
        y = q.front().s;
        q.pop();
        cnt++;
        for(int k = 0;k < 4;k++){
            nx = x + posx[k];
            ny = y + posy[k];
            if(nx < 0 || ny < 0 || nx >= n || ny >= m)
                continue;

            if(board[nx][ny] == 1){
                q.push(mp(nx,ny));
                board[nx][ny] = 0;
            }
        }
    }
    // if(cnt > 1){
        mx = max(cnt,mx);
    // }
}


void solve(){

    cin >> n >> m;

    string s;

    for(int i = 0;i < n;i++){
        cin >> s;
        for(int j = 0;j < m;j++){
            board[i][j] = s[j] - '0';
        }
    }

    for(int i = 0;i < n;i++){
        for(int j = 0;j < m;j++){
            if(board[i][j] == 1){
                board[i][j] = 0;
                q.push(mp(i,j));
                dfs();
            }
        }
    }


    cout << mx;

    return;
}
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    ll q;
 
    // cin >> q;

    // while(q--)
        solve(); 

    return 0;
}