题解 | 判断质数

#include <iostream>
using namespace std;

bool isprime(unsigned long long n){
    if(n==1){
        return false;
    }else if(n<=3){
        return true;
    }
    for(unsigned long long i=2; i*i<=n; ++i){
        if(n%i==0) return false;
    }
    return true;
}


int main() {
    unsigned long long n;
    cin >> n;
    if(isprime(n)){
        cout << "Yes\n" ;
    }else{
        cout << "No\n" ;
    }
}
// 64 位输出请用 printf("%lld")