int pre[8]={4123,1324,1234,1324,1243,2413,2134,4123};

LL solve(LL n)
{
     if (n/10000==0)
     return 4123;

     int k,j,i,p,b[5]={0};
     LL m=0;
     LL res=10000;
     while (true)
      {
          p=n%10;
          n/=10;

          if (p==0)
             b[0]++;
          else
          if (p==1 && !b[1])
           b[1]=1;
           else
          if (p==2 && !b[2])
           b[2]=1;
           else
           if (p==3 && !b[3])
           b[3]=1;
           else
           if (p==4 && !b[4])
           b[4]=1;
            else
             {
                  m+=p*res;
                  res*=10;
             }
             if(n==0) break;
      }

      if (m==0)
      {
         i=-1;
         res=1;
         for (j=1;j<=b[0];j++)
          res*=(LL)10;
          while (true)
          {
              i++;
              if ((pre[i]*res)%7==0)
                 break;
          }
          return pre[i]*res;
      }
      else
      if(b[0]>0)
       {
        for (i=0;i<b[0];i++)
        {
         m*=(LL)10;
         res*=(LL)10;
        }
        k=m%7;
        return m+pre[7-k];
       }

      else
      {
      k=m%7;
      m+=pre[7-k];
      return m;
      }
}

where LL is unsigned long long. Can give me some tests if possible

Edited by author 19.07.2006 14:18