[模板] Miller-Rabin 素数测试

细节挺多的。。

#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<ctime>

using namespace std;

typedef long long ll;

ll mul(ll a,ll b,ll mod) {
    ll ret = 0ll;
    a %= mod;
    while( b ) {
        if ( b & 1ll ) ret = ( ret + a ) % mod, b--;
        b >>= 1ll;
        a = ( a + a ) % mod;
    }
    return ret;
}

ll qpow(ll a,ll b,ll mod) {
    ll ret = 1ll;
    a %= mod;
    while( b ) {
        if ( b & 1ll ) ret = mul(ret,a,mod),b--;
        b >>= 1ll;
        a = mul(a,a,mod);
    }
    return ret;
}

ll ter[15]= {0,2,3,5,7,11,13,17,19,23,29};
const int TOP=10;
bool Miller_Rabin(ll n) {
    if ( n==2ll||n==3ll ) return true;
    if ( !( n & 1ll ) ) return false;
    ll d = n - 1ll;
    int s = 0;
    while( !( d & 1ll ) ) ++s, d>>=1ll;
    for(int i=1; i<=TOP; i++) {
        ll a = ter[i];
        if(a>=n) return true;
        ll x = qpow(a,d,n);
        ll y = 0ll;
        for(int j=0; j<s; j++) {
            y = mul(x,x,n);
            if ( 1ll == y && 1ll != x && n-1ll != x ) return false;
            x = y;
        }
        if ( 1ll != y ) return false;
    }
    return true;
}

int main() {
    ll x;
    while(cin>>x) {
        Miller_Rabin(x)?cout<<"YES
":cout<<"NO
";
    }
    return 0;
}