题解 | 素数判定

#include <iostream>
#include <cmath>

using namespace std;

int my_gcd(int a, int b)
{
    if(b == 0) return a;
    else
    {
        return my_gcd(b, a % b);
    }
}

int main() 
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n;
    while(cin >> n)
    {
        if(n == 1)
        {
            cout << "no" << "\n";
            continue;
        }
        int is = 1;
        for(int i = 1; i <= sqrt(n); i++)
        {
            if(my_gcd(n, i) != 1)
            {
                cout << "no" << "\n";
                is = 0;
                break;
            }
        }
        if(is == 1) cout << "yes" << "\n";
    }
    return 0;
}