> llong is_prime(llong n)
> {
>     llong old = n;
>     if (n%2 == 0)
>         return 2;
>         
>     llong limit = llong(sqrt(n*1.0)) + 1;
>     if (limit%2 == 0)   --limit;
> 
>     do{
>         if (n%limit == 0)
>         {
>             n = limit;
>             limit = llong(sqrt(n*1.0))+1;
>             if (limit%2 == 0) --limit;
>         }
>         else
>             limit -= 2;
>     }while (limit >= 3);
>     if (old == n)
>         return 1;
>     else
>         return n;
> }

• 18014398509481931是素数还是合数啊 (43) y07yangruilong 2007-11-03 10:48:17
  • Re:18014398509481931是素数还是合数啊 (28) shanhuhai 2007-11-09 08:13:27
    • Re:18014398509481931是素数还是合数啊 (78) xiaoyao3857 2012-03-25 20:49:38
• Re:18014398509481931 (7) lvhao945 2009-12-14 22:17:16