随机素数测试模板

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LL arr[5]={ 2,3,5,233,331 };
LL Qmul( LL a , LL b , LL mod )
{
    LL res = 0;
    while ( b )
    {
        if ( b&1 )
            res = ( res+a )%mod;
        a = ( a+a )%mod;
        b = b>>1;
    }
    return res;
}
LL Qpow( LL a , LL b , LL mod )
{
    LL res = 1;
    while ( b )
    {
        if ( b&1 )
            res = Qmul( res , a , mod );
        a = Qmul( a , a , mod );
        b = b>>1;
    }
    return res;
}
bool Miller_Rabin( LL n )
{
    if ( n==2 ) return true;
    if ( n <2||n%2==0 ) return false;
    LL m = n-1,k = 0;
    while ( m%2==0 ) k++,m >>= 1;
    for ( int i=0 ; i<5 ; i++ )
    {
        LL a = arr[i]%(n-1)+1;
        LL x = Qpow( a , m , n );
        for ( int j=1 ; j<=k ; j++ )
        {
            LL y = Qmul( x , x , n );
            if ( y==1&&x!=1&&x!=n-1 )
                return false;
            x = y;
        }
        if ( x!=1 ) return false;
    }
    return true;
}