同poj 1059，判断是否为前缀。

1 #include 
     
       2 #include 
      
        3 const int N = 100000; 4 int next[N][10],cnt=0; 5 bool f=1,end[N],vis[N]; 6 void inst(char *s) 7 { 8     int u=0,p; 9     for(;*s;s++)10     {11         p = *s - '0';12         if(end[u])13         {f = 0; return ;}14         if(!next[u][p])15         {16             cnt++;17             memset(next[cnt],0,sizeof next[0]);18             next[u][p] = cnt;19             vis[u] = 1;20         }21         u = next[u][p];22     }23     end[u] = 1;24     if(vis[u]) f = 0;25 }26 int main()27 {28     char t[12];29     int n,m;30     scanf("%d",&n);31     while(n--)32     {33         scanf("%d",&m);34         while(m--)35         {36             scanf("%s",t);37             if(f) inst(t);38         }39         printf("%s\n",f ?"YES" :"NO");40         f = 1; cnt = 0;41         memset(next[0],0,sizeof next[0]);42         memset(end,0,sizeof end);43         memset(vis,0,sizeof end);44     }45     return 0;46 }