欧拉筛+二分判断是否存在

#include<bits/stdc++.h>
using namespace std;

vector<int>prime;

void sieve(int n){
    vector<bool>isprime(n+1,true);
    for (int i=2;i<=n;i++){
        if (isprime[i])
            prime.push_back(i);
        for (int p:prime){
            if (p*i>n)
                break;
            isprime[p*i]=false;
            if (i%p==0)
                break;
        }
    }
}
string judge(int n){
    if (binary_search(prime.begin(),prime.end(),n)) return "Yes";
    else return "No";
}
int main(){
    sieve(10000);
    int n;cin>>n;cout<<judge(n);
}