[백준 BoJ] 2636 - 치즈

// https://www.acmicpc.net/problem/2636
// 치즈
#include<iostream>
#include<queue>
#include<cstring>
#include<vector>

using namespace std;
int N, M, cnt = 0, time = 0;
int map[102][102];
int visited[102][102];
int dx[] = { 1,-1,0,0 };
int dy[] = { 0,0,1,-1 };

queue<pair<int, int>> q;
vector<int> cv;
void bfs() {

	while (cnt) {
		memset(visited, 0, sizeof(visited));

		visited[0][0] = true;
		q.push({ 0,0 });
		cv.push_back(cnt);
		
		while (!q.empty()) {
			int x = q.front().first;
			int y = q.front().second;
			q.pop();

			for (int i = 0; i < 4; i++) {
				int nx = x + dx[i];
				int ny = y + dy[i];

				if (nx < 0 || ny < 0 || nx >= N || ny >= M) continue;

				if (map[nx][ny] == 0 && !visited[nx][ny]) {
					visited[nx][ny] = true;
					q.push({ nx,ny });
				}
				else if (map[nx][ny] == 1 && !visited[nx][ny]) {
					visited[nx][ny] = true;
					map[nx][ny] = 0;
					cnt--;
				}
			}
		}
		time++;
		
	}

}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
	
	cin >> N >> M;

	for (int i = 0;  i < N; i++) {
		for (int j = 0; j < M; j++) {
			cin >> map[i][j];
			if (map[i][j] == 1) cnt++;
		}
	}

	bfs();

	cout << time << "\n" << cv[cv.size()-1];
	


}

• BFS