Submission

Score: 100

User: singtoppy

Problemset: เกาะที่ใหญ่ที่สุด

Language: cpp

Time: 0.003 second

Submitted On: 2026-02-08 13:45:06

#include<bits/stdc++.h>

using namespace std;

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

	int n, m;
	cin >> n >> m;

	vector<vector<int>> v(n, vector<int>(m));

	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			char c;
			cin >> c;

			v[i][j] = c - '0';
		}
	}	

	const int dir[4][2] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
	int res = 0;

	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			if(v[i][j] == 0) {
				continue;
			}

			queue<pair<int, int>> q;
			q.push({i, j});

			int cnt = 0;
			while(!q.empty()) {
				auto [y, x] = q.front();
				q.pop();

				if(v[y][x] == 0) {
					continue;
				}

				cnt++;
				res = max(res, cnt);
				v[y][x] = 0;

				for(const auto& d : dir) {
					const int nx = x + d[1];
					const int ny = y + d[0];

					if(nx >= 0 && nx < m && ny >= 0 && ny < n && v[ny][nx] != 0) {
						q.push({ny, nx});
					}
				}
			}
		}
	}

	cout << res;

	return 0;
}