171111_7576_토마토

	#include <iostream> #include <queue>//bfs
	using namespace std;
	int box[1002][1002];
	int ripen[1002][1002];
	struct xy
	{
	int x;
	int y;
	};
	int main()
	{
	queue<xy> q;
	int M, N;
	cin >> M >> N;
	int cnt=0;
	int result=0;
	for(int i=0; i<=M+1; i++)
	{
	box[0][i]=1;
	box[N+1][i]=1;
	}
	for(int i=1; i<=N; i++)
	{
	box[i][0]=1;
	box[i][M+1]=1;
	}
	for(int i=1; i<=N; i++)
	{
	for(int j=1; j<=M; j++)
	{
	xy tomato;
	cin >> box[i][j];
	ripen[i][j]=box[i][j];
	if(box[i][j]==1)
	{
	cnt++;
	tomato.x=j;
	tomato.y=i;
	q.push(tomato);
	}
	}
	}
	bool chk1;
	while(!q.empty())
	{
	int cnt_while=0;
	for(int i=0; i<cnt; i++)
	{
	chk1=1;
	xy now=q.front();
	q.pop();
	xy adj;
	if(box[now.y-1][now.x]==0 && ripen[now.y-1][now.x]==0)
	{
	adj.y=now.y-1;
	adj.x=now.x;
	q.push(adj);
	ripen[adj.y][adj.x]=1;
	cnt_while++;
	chk1=0;
	}
	if(box[now.y][now.x+1]==0 && ripen[now.y][now.x+1]==0)
	{
	adj.y=now.y;
	adj.x=now.x+1;
	q.push(adj);
	ripen[adj.y][adj.x]=1;
	cnt_while++;
	chk1=0;
	}
	if(box[now.y+1][now.x]==0 && ripen[now.y+1][now.x]==0)
	{
	adj.y=now.y+1;
	adj.x=now.x;
	q.push(adj);
	ripen[adj.y][adj.x]=1;
	cnt_while++;
	chk1=0;
	}
	if(box[now.y][now.x-1]==0 && ripen[now.y][now.x-1]==0)
	{
	adj.y=now.y;
	adj.x=now.x-1;
	q.push(adj);
	ripen[adj.y][adj.x]=1;
	cnt_while++;
	chk1=0;
	}
	}
	cnt=cnt_while;
	result++;
	}
	for(int i=1; i<=N; i++)
	{
	for(int j=1; j<=M; j++)
	if(ripen[i][j]==0)
	{
	cout << "-1";
	return 0;
	}
	}
	if(chk1 && result==2) cout << "-1";
	else cout << result-1;
	system("pause");
	}