hdu1241 基础BFS

#include<cstdio>
#include<cstring>
#include<queue>
struct node
{
	int x,y;
	node(int x = 0,int y = 0) : x(x),y(y){}
};
const int maxn = 200;
int dx[8] = {0,1,1,1,-1,-1,0,-1};
int dy[8] = {1,1,0,-1,0,-1,-1,1};
std::queue<node>q;
int vis[maxn][maxn];
char map[maxn][maxn];
int n,m;

void BFS(int i,int j)
{
	q.push(node(i,j));
	while(!q.empty())
	{
		int x = q.front().x;
		int y = q.front().y;
		q.pop();
		for(int i =0;i<8;i++)
		{
			int x1 = x + dx[i];
			int y1 = y + dy[i];
			if(x1 < 0 || x1 >= n || y1 < 0 || y1 >= m)continue;
			if(!vis[x1][y1] && map[x1][y1] == ‘@‘)
			{
				vis[x1][y1] = 1;
				q.push(node(x1,y1));
			}
		}
	}
}

int main()
{
	int i,j;
	while(scanf("%d%d",&n,&m),n+m)
	{
		while(!q.empty())q.pop();
		int sum = 0;
		for(i=0;i<n;i++)
		{
			scanf("%s",map[i]);
		}
		memset(vis,0,sizeof(vis));
		for(i=0;i<n;i++)
		{
			for(j=0;j<m;j++)
			{
				if(map[i][j] == ‘@‘ && !vis[i][j])
				{
					sum ++;
					vis[i][j] = 1;
					BFS(i,j);
				}
			}
		}
		printf("%d\n",sum);
	}
	return 0;
}