hdu 变形课（简单搜索）

/*

用二位数组保存数据，接着一行一行搜

*/

#include<iostream>
#include<string>
#include<cstring>
using namespace std;
int mark[30][30], dis[30];
bool p = false;

void work(int ch)
{
	int i;
	if(ch == 12)
		p = true;
	for( i=0; i < 26; i++ )
	{
		if(mark[ch][i] == 1 && dis[i] == 0)
		{
			dis[i] = 1;
			work(i);
		}
	}
}

int main()
{
	char str[100];
	memset(mark, 0, sizeof(mark));
	memset(dis, 0, sizeof(dis));
	while(scanf("%s", str) != -1)
	{
		p = false;
		if(strcmp(str, "0")==0)
		{
			printf("No.\n");
			continue;
		}
		int len;
		len = strlen(str);
		mark[str[0]-'a'][str[len-1]-'a'] = 1;
		while(scanf("%s", str) && strcmp(str,"0"))
		{
			len = strlen(str);
			mark[str[0]-'a'][str[len-1]-'a'] = 1;
		}
		dis[1] = 1;
		work(1);
		if(p)
			printf("Yes.\n");
		else
			printf("No.\n");
		memset(dis, 0, sizeof(dis));
		memset(mark, 0, sizeof(mark));
	}
	return 0;
}