POJ3641:Pseudoprime numbers（判断是否为Carmichael numbers，挑战P122）

/*快速幂， Carmicharl numbers*/
#include <iostream>
#include <stdio.h>
#include <algorithm>

using namespace std;
typedef long long ll;
ll a, p;

bool ok_prime(ll t)        //如果是素数，直接输出no
{
    if(t == 2)
        return 1;
    else{
        for(int i = 2; i * i < t; i++){
            if(t % i == 0)
                return 0;
        }
        return 1;
    }
}
 ll mod_pow(ll n, ll m)
 {
     ll res = 1;
     ll l;
     l = m;
     while(l > 0){
        if(l & 1){
            res = res * n % m;
        }
        n = n * n % m;
        l >>= 1;
     }
     return res;
 }

int main()
{
    while(scanf("%l64d%l64d", &p, &a) != EOF){
        if(a == 0 && p == 0)
            break;
        if(ok_prime(p))
            printf("no\n");
        else{
            if(mod_pow(a, p) == a)
                printf("yes\n");
            else
                printf("no\n");
        }
    }
    return 0;
}