1 /* 2 11509672    2014-08-21 11:32:55    Accepted     3 1200    0MS    380K    442 B    G++    空信高手 4 */ 5 #include<iostream> 6 #include<string> 7 #include<cstdio> 8 using namespace std; 9 int main()10 {11     //freopen("input.txt","r",stdin);12     string str;13     int n,flag=1;14     while(cin>>n && n!=0)15     {16         cin>>str;17         int pnt;18         for(int i=1;i<=n;i++)19         {20             flag=1;//重置左右21             pnt=i;22             while(pnt<=str.length())23             {24                 cout<<str[pnt-1];25                 //左右分别讨论26                 if(flag){pnt+=(2*n-2*i+1);flag=0;} 27                 else {pnt+=(2*i-1);flag=1;}28             }29         }30         cout<<endl;31     }32     return 0;33 }