hdu 1181

额，简单的DFS

#include<iostream>
#include<queue>
using namespace std;
int map[26][26];
bool vis[26][26];
struct node
{
	int x;
	node(int _x=0):x(_x){};
};
bool bfs()
{
	queue<node> Q;
	Q.push(node(1));
	while(!Q.empty())
	{
		node t=Q.front();
		Q.pop();
		for(int i=0;i<26;i++)
		{
			if(map[t.x][i]&&i=='m'-'a')
				return true;
			if(!vis[t.x][i]&&map[t.x][i])
			{
				vis[t.x][i]=1;
				Q.push(node(i));
			}
		}
	}
	return false;
}
int main()
{
	char str[100];
	memset(map,0,sizeof(map));
	while(cin>>str)
	{
		if(strcmp(str,"0")==0)
		{
			memset(vis,0,sizeof(vis));
	      if(bfs())
		    cout<<"Yes."<<endl;
        	else cout<<"No."<<endl;
			memset(map,0,sizeof(map));
			continue;
		}
		int len =strlen(str);
		map[str[0]-'a'][str[len-1]-'a']=1;
	}
	return 0;
}