Submission

Score: 100

User: chs_14

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.003 second

Submitted On: 2026-03-07 21:48:42

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

pair<int, int> direct[] = {{-1,0},{1,0},{0,-1},{0,1}};

int bfs(int m, int n, int y, int x, vector<string> &sea) {
    int counter=1;
    queue<pair<int, int>> q;
    q.push({y, x});
    sea[y][x]='0';

    while (!q.empty())
    {
        pair<int, int> e = q.front(); q.pop();

        for (int i = 0; i < 4; i++)
        {
            int ndy=e.first+direct[i].first, ndx=e.second+direct[i].second;

            if (ndy>=0 && ndy<m && ndx>=0 && ndx<n && sea[ndy][ndx]=='1') {
                    sea[ndy][ndx]='0';
                    ++counter;
                    q.push({ndy, ndx});
                }
        }
    }
    return counter;
}

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

    int n, m, maxisland=0;
    cin >> m >> n;
    vector<string> sea(m);
    for (int i = 0; i < m; i++)
    {
        cin >> sea[i];
    }

    for (int i = 0; i < m; i++)
    {
        for (int j = 0; j < n; j++)
        {
            if (sea[i][j]=='1') maxisland = max(maxisland, bfs(m, n, i, j, sea));
        }
    }
    cout << maxisland;

    return 0;
}