Pseudoprime numbers（POJ 3641 快速幂）

 #include <cstring>
 #include <cstdio>
 #include <iostream>
 #include <cmath>
 #include <algorithm>
 using namespace std;
 #define LL long long
 LL p,res,a;
 bool judge_prime(LL k)
 {
     LL i;
     LL u=int(sqrt(k*1.0));
     for(i=;i<=u;i++)
     {
         if(k%i==)
             return ;
     }
     return ;
 }
 int main()
 {
     freopen("in.txt","r",stdin);
     while(scanf("%lld%lld",&p,&a))
     {
         if(p==&&a==)
             break;
         if(judge_prime(p))
         {
             printf("no\n");
             continue;
         }
         res=;
         LL t=p;
         LL w=a;
         while(p)
         {
             if(p&) res=(res*a)%t;
             a=(a*a)%t;
             p>>=;
         }
         if(res==w)
             printf("yes\n");
         else
             printf("no\n");
     }
 }