(1) [C++, Java] 백준 No.10866 : 덱(기본구현)

문제

풀이

# C++(직접구현)

심화과정을 거치고 난 뒤 할 것

# C++(STL 사용)

#include <iostream>
#include <deque>

using namespace std;

int main(void)
{
    ios::sync_with_stdio(false);

    deque<int> deq;

    int N;
    cin >> N;
    
    while(N--)
    {
        string cmd;
        cin >> cmd;

        if (cmd == "push_front")
        {
            int num;
            cin >> num;
            deq.push_front(num);
        }

        else if (cmd == "push_back")
        {
            int num;
            cin >> num;
            deq.push_back(num);
        }

        else if (cmd == "pop_front")
        {
            if (!deq.empty()){
                 cout << deq.front() << endl;
                 deq.pop_front();   
            }
            else
                cout << -1 << endl;
        }

        else if (cmd == "pop_back")
        {
            if (!deq.empty()){
                 cout << deq.back() << endl;
                 deq.pop_back();   
            }
            else
                cout << -1 << endl;
        }

        else if (cmd == "front")
        {
            if (!deq.empty())
                 cout << deq.front() << endl;
            else
                cout << -1 << endl;
        }

        else if (cmd == "back")
        {
            if (!deq.empty())
                 cout << deq.back() << endl;
            else
                cout << -1 << endl;
        }

        else if (cmd == "size")
            cout << deq.size() << endl;

        else if (cmd == "empty")
            cout << deq.empty() << endl;
    }
}

# Java

import java.util.*;

public class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        sc.nextLine();
        ArrayDeque<Integer> queue = new ArrayDeque<Integer>();
        for (int k=0; k<n; k++) {
            String line = sc.nextLine();
            String[] s = line.split(" ");
            String cmd = s[0];
            if (cmd.equals("push_front")) {
                int num = Integer.parseInt(s[1]);
                queue.offerFirst(num);
            } else if (cmd.equals("push_back")) {
                int num = Integer.parseInt(s[1]);
                queue.offerLast(num);
            }  else if (cmd.equals("front")) {
                if (queue.isEmpty()) {
                    System.out.println("-1");
                } else {
                    System.out.println(queue.peekFirst());
                }
            } else if (cmd.equals("size")) {
                System.out.println(queue.size());
            } else if (cmd.equals("empty")) {
                if (queue.isEmpty()) {
                    System.out.println("1");
                } else {
                    System.out.println("0");
                }
            } else if (cmd.equals("pop_front")) {
                if (queue.isEmpty()) {
                    System.out.println("-1");
                } else {
                    System.out.println(queue.pollFirst());
                }
            } else if (cmd.equals("pop_back")) {
                if (queue.isEmpty()) {
                    System.out.println("-1");
                } else {
                    System.out.println(queue.pollLast());
                }
            } else if (cmd.equals("back")) {
                if (queue.isEmpty()) {
                    System.out.println("-1");
                } else {
                    System.out.println(queue.peekLast());
                }
            }
        }
    }
}