HDOJnbsp;nbsp;1181nbsp;nbsp;nbsp;nbsp;变形课

题目：http://acm.hdu.edu.cn/showproblem.php?pid=1181

#include<iostream>
#include <cstdio>
#include<cstring>
using namespace std;
struct
{
    char beg;
    char end;
}M[101];
bool hash[101],f;
int N;
bool DFS(char ch)
{
     if(ch =='m')
     {
         f= rue;
         return true;
     }
     for(int i = 0;i<N;++i)
         if(M[i].beg==ch&&!hash[i])
         {
            hash[i] = true;
            DFS ( M[i].end );
            hash[i] = false;
         }
     return false;
}
int main ()
{
    string str;
    while (cin >>str)
    {
        N = 0;
        f = false;
        memset ( hash, 0 , sizeof ( hash ) );
        while ( str != "0" )
        {
            M[N].beg = str[0];
            M[N].end = str[ str.size() - 1 ];
            N++;
            cin >> str;
        }
        DFS ( 'b' );
        puts ( f ? "Yes." : "No." );
    }
    return 0;
}