http://www.bnuoj.com/v3/contest_show.php?cid=7612#info

http://www.bnuoj.com/v3/contest_show.php?cid=7612#problem/

题解：http://bestcoder.hdu.edu.cn/blog/2015-multi-university-training-contest-7-solutions-by-uestc/

水题：

#include 
     
      #include
      
       using namespace std;int sum,x;void get_sum(int n){    while(n)    {        sum += n%10;        n /= 10;    }}void get_x(){    int times = 1;    int s = sum;    while(s)    {        s /= 10;        times *= 10;    }    x = (x * times)+sum;    x = x%11;}int main(){    int n,t;    int cas = 1;    while(cin>>n>>t && (n!=-1||t!=-1))    {        sum = 0;        x = 0;        x = n%11;        get_sum(n);        for(int i = 1;i <= t;i ++){                get_x();                get_sum(sum);        }        if(x == 0)            printf("Case #%d: Yes\n",cas++);        else if(x)            printf("Case #%d: No\n",cas++);    }    return 0;}