HDOJ  1181    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
.beg = str[0];


M
.end = str[ str.size() - 1 ];


N++;


cin >> str;


}


DFS ( 'b' );


puts ( f ? "Yes." : "No." );

}

return
0;

}