10845 - 큐

solution

code

#include <iostream>
#include <queue>
using namespace std;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int N;
    cin >> N;
    string cmd;
    queue<int> queue;
    int arg;
    
    for(int i = 0; i < N; i++)
    {
        cin >> cmd;
        if(cmd == "push")
        {
            cin >> arg;
            queue.push(arg);
        }
        else if(cmd == "pop")
        {
            if(queue.empty()) cout << -1 << endl;
            else
            {
                cout << queue.front() << endl;
                queue.pop();
            }
        }
        else if(cmd == "size")
        {
            cout << queue.size() << endl;
        }
        else if(cmd == "empty")
        {
            if(queue.empty()) cout << 1 << endl;
            else cout << 0 << endl;
        }
        else if(cmd == "front")
        {
            if(queue.empty()) cout << -1 << endl;
            else cout << queue.front() << endl;
        }
        else if(cmd == "back")
        {
            if(queue.empty()) cout << -1 << endl;
            else cout << queue.back() << endl;
        }
    }

    return 0;
}

ref

10845번: 큐