10866 - 덱

solution

code

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

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

    int N;
    cin >> N;
    deque<int> deque;
    string cmd;
    int arg;

    for(int i = 0; i < N; i++)
    {
        cin >> cmd;
        if(cmd == "push_front")
        {
            cin >> arg;
            deque.push_front(arg);
        }
        else if(cmd == "push_back")
        {
            cin >> arg;
            deque.push_back(arg);
        }
        else if(cmd == "pop_front")
        {
            if(deque.empty()) cout << -1 << '\n';
            else
            {
                cout << deque.front() << '\n';
                deque.pop_front();
            }
        }
        else if(cmd == "pop_back")
        {
            if(deque.empty()) cout << -1 << '\n';
            else
            {
                cout << deque.back() << '\n';
                deque.pop_back();
            }
        }
        else if(cmd == "size")
        {
            cout << deque.size() << '\n';
        }
        else if(cmd == "empty")
        {
            if(deque.empty()) cout << 1 << '\n';
            else cout << 0 << '\n';
        }
        else if(cmd == "front")
        {
            if(deque.empty()) cout << -1 << '\n';
            else
            {
                cout << deque.front() << '\n';
            }
        }
        else if(cmd == "back")
        {
            if(deque.empty()) cout << -1 << '\n';
            else
            {
                cout << deque.back() << '\n';
            }
        }
    }

    return 0;
}

ref

10866번: 덱