HDU 2138 How many prime numbers

米勒罗宾素数测试：

/*

  if n < 1,373,653, it is enough to test a = 2 and 3.

  if n < 9,080,191, it is enough to test a = 31 and 73.

  if n < 4,759,123,141, it is enough to test a = 2, 7, and 61.

  if n < 2,152,302,898,747, it is enough to test a = 2, 3, 5, 7, and 11.

*/

#include <cstdio>

long long power(long long m,long long n,long long k)

{

    long long b = 1;

    while (n>0)

    {

        if (n&1) b=(b*m)%k;

        n=n>>1;

        m=(m*m)%k;

    }

    return b;

} 



bool Miller_Rabbin(long long t)

{

    if (t==2) return true;

    if (power(2,t-1,t)!=1) return false;

    if (power(7,t-1,t)!=1) return false;

    if (power(61,t-1,t)!=1) return false;

    return true;

}

    

int main()

{

    int n;

    while(scanf("%d",&n)!=EOF)

    {

        int x,ans;

        ans=0;

        for (int i=0; i<n; i++)

        {

            scanf("%d",&x);

            if (Miller_Rabbin(x)) ans++;

        }

        printf("%d\n",ans);

    }    

}