改了一下午结果x打成y.....

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

queue<int> q;

void spush(int x){
    q.push(x);
}

void spop(){
    if(q.empty()) cout << "impossible!" << endl;
    else{
        q.pop();
    }
}

void stop(){
    if(q.empty()) cout << "impossible!" << endl;
    else cout << q.front() << endl;
}

int main(){
    int n;
    cin >> n;
    while(n--){
        int x,y;
        cin >> x;
        if(x==1){
            cin >> y;
            spush(y);
        }else if(x==2){
            spop();
        }else if(x==3){
            stop();
        }
    }
}