题解 | 【模板】队列

#include <iostream>
using namespace std;

const int N = 100001;
int n,q[N],h,t;

void push(int x){
    q[t++] = x;
}

void pop(){
    if(h==t) cout<<"error\n";
    else cout<<q[h++]<<"\n";
}

void front(){
    if(h==t) cout<<"error\n";
    else cout<<q[h]<<"\n";
}


int main() {
    cin>>n;
    while(n--){
        string op;
        cin>>op;
        if("push"==op){
            int x;
            cin>>x;
            push(x);

        }
        else if("pop"==op){
            pop();
        }
        else{
            front();
        }
    }

    return 0;
}

#牛客春招刷题训练营#https://www.nowcoder.com/discuss/727521113110073344