题目链接：https://www.acwing.com/problem/content/831/

数组模拟队列

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 const int N=1e5+10;
 4 int a[N];
 5 int h=0,t=0,n;
 6 int main()
 7 {
 8     cin>>n;
 9     while(n--){
10         string s;
11         int x;
12         cin>>s;
13         if(s=="push"){
14             cin>>x;
15             a[++t]=x;
16         }else if(s=="pop"){
17             ++h;
18         }else if(s=="empty"){
19             if(h>=t){
20                 cout<<"YES"<<endl;
21             }else{
22                 cout<<"NO"<<endl;
23             }
24         }else if(s=="query"){
25             cout<<a[h+1]<<endl;
26         }
27     }
28     return 0;
29 }