hdu 1181 以b开头m结尾的咒语 (DFS)

咒语是以a开头b结尾的一个单词,那么它的作用就恰好是使A物体变成B物体
现在要将一个B(ball)变成一个M(Mouse),
比如 "big-got-them".

Sample Input
so
soon
river
goes
them
got
moon
begin
big
0

Sample Output
Yes.

 # include <cstdio>
 # include <cmath>
 # include <iostream>
 # include <cstring>
 # include <algorithm>
 using namespace std ;

 int l = ,flag = ;

 struct Node
 {
     char head,end;
 } c[];
 int vis[];

 void dfs(char ch)
 {
     int i;
     if(ch == 'm')
         flag = ;
     if(flag)
         return;
     for(i = ; i<l; i++)
     {
         if(vis[i])
             continue;
         if(c[i].head == ch)
         {
             vis[i] = ;
             dfs(c[i].end);
             vis[i] = ;
         }
     }
 }

 int main()
 {
     //freopen("in.txt","r",stdin) ;
     char s[];
     int i;
     while(~scanf("%s",s))
     {
         if(!strcmp(s,""))
             continue;
         l = ;
         c[l].head = s[];
         c[l].end = s[strlen(s)-];
         l++;
         while(scanf("%s",s))
         {
             if (strcmp(s,"") == )
                 break ;
             c[l].head = s[];
             c[l].end = s[strlen(s)-];
             l++;
         }
         flag = ;
         for(i = ; i<l; i++)
         {
             if(c[i].head == 'b')
             {
                 memset(vis,,sizeof(vis));
                 vis[i] = ;
                 dfs(c[i].end);
             }
             if(flag)
                 break;
         }
         if(flag)
             printf("Yes.\n");
         else
             printf("No.\n");
     }

     return ;
 }