queue 的使用

#include<iostream>
#include<queue>
#include<stack>
#include<string>
using namespace std;
int main(){
    int t;cin>>t;
    while(t--){
        int n;string str;
        cin>>n>>str;
        
        int inNum;string str1;
        queue<int>Q;
        stack<int>S;
        for(int i=0; i<n; i++){
            if(str=="FIFO"){//队列
                cin>>str1;
                if(str1=="IN"){
                    cin>>inNum;
                    Q.push(inNum);
                }
                if(str1=="OUT"){
                    if(Q.empty()){
                        cout<<"None"<<endl;
                    } 
                    else{
                        cout<<Q.front()<<endl;Q.pop();
                    }
                }
            }
            else{//栈
                cin>>str1;
                if(str1=="IN"){
                    cin>>inNum;
                    S.push(inNum);
                }
                if(str1=="OUT"){
                    if(S.empty()){
                        cout<<"None"<<endl;
                    } 
                    else {
                        cout<<S.top()<<endl;S.pop();
                    }
                }
            }
        }
    }
}