DFS

HDU1181  http://acm.hdu.edu.cn/showproblem.php?pid=1181

#include<stdio.h>
#include<algorithm>
#include<iostream>
#include<string.h>
using namespace std;
struct point{
char first;
char last;
}p[1111];
int flag,k;
char s[1111];
char vis[1111],ma[1111];
void dfs(char c){
if(c=='m'){
    flag=1;
    return;
}
for(int j=0;j<k;j++){
    if(vis[j]==0&&p[j].first==c){
            vis[j]=1;
        dfs(p[j].last);
    }
}
return ;
}
int main()
{
    while(~scanf("%s",&s)){
            if(strcmp(s,"0")==0)continue;
            p[0].first=s[0];
            p[0].last=s[strlen(s)-1];
    k=1;
        while(~scanf("%s",&s)&&strcmp(s,"0")!=0)
        {p[k].first=s[0];
    p[k].last=s[strlen(s)-1];
    //cout<<p[k].first<<p[k].last<<endl;
    k++;

        }
    flag=0;
        for(int i=0;i<k;i++){
            if(p[i].first=='b'){
                memset(vis,0,sizeof(vis));
                vis[i]=1;
                dfs('b');
            }
            if(flag==1)break;
        }
        if(flag==1)
            cout<<"Yes."<<endl;
        else cout<<"No."<<endl;
    }
}