Submission

Score: 100

User: SnowAveNode

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.003 second

Submitted On: 2026-04-10 18:21:11

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

const int nx = 1e5 + 5, MOD = 1e9 + 7, inf = 2e9; const ll INF = 4e18;
int dy[] = {-1, 1, 0, 0}, dx[] = {0, 0, -1, 1};

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);

    int n, m; cin >> n >> m; ll ans = 0;
    vector<vector<char>> grid(n, vector<char>(m));
    for(auto &x : grid) for(auto &y : x) cin >> y;

    for(int i = 0; i < n; i++)
        for(int j = 0; j < m; j++)
            if(grid[i][j] == '1') {
                ll area = 0;
                stack<pair<int, int>> st;
                st.push({i, j});
                grid[i][j] = '0';
                area++;

                while(!st.empty()) {
                    auto [y, x] = st.top(); st.pop();
                    
                    for(int k = 0; k < 4; k++) {
                        int ny = y + dy[k], nx = x + dx[k];
                        if(ny < 0 || ny >= n || nx < 0 || nx >= m) continue;
                        if(grid[ny][nx] == '0') continue;
                        grid[ny][nx] = '0';
                        area++;
                        st.push({ny, nx});
                    }
                }

                ans = max(ans, area);
            }
    
    cout << ans << '\n';

    return 0;
}