老师教的，不对找我老师

#include<bits/stdc++.h> 
using namespace std;
const int N=1e6+10;
int main(){
	int n,a[N],b,m;
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	sort(a+1,a+1+n);
	cin>>m;
	for(int i=1;i<=m;i++){
		cin>>b;
		int r=n+1,l=0;
		while(r-l>1){
			int mid=(r+l)/2;
			if(a[mid]>=b){
				r=mid;
			} else {
				l=mid;
			}
		}
		if(r<=n&&a[r]==b){
			cout<<"YES"<<endl;
		} else {
			cout<<"NO"<<endl;
		}
	}
	return 0;
}