[JAVA] 백준 10866번- 덱

https://www.acmicpc.net/problem/10866

10866번: 덱

 

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Deque;
import java.util.LinkedList;
import java.util.StringTokenizer;

public class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();

        int n = Integer.parseInt(br.readLine());

        Deque<Integer> deque = new LinkedList<>();

        for(int i=0; i<n; i++){
            StringTokenizer st = new StringTokenizer(br.readLine());
            String str = st.nextToken();

            switch(str){
                case "push_front":
                    deque.addFirst(Integer.parseInt(st.nextToken()));
                    break;
                case "push_back":
                    deque.addLast(Integer.parseInt(st.nextToken()));
                    break;
                case "pop_front":
                    if(deque.isEmpty()) sb.append(-1).append("\n");
                    else sb.append(deque.removeFirst()).append("\n");
                    break;
                case "pop_back":
                    if(deque.isEmpty()) sb.append(-1).append("\n");
                    else sb.append(deque.removeLast()).append("\n");
                    break;
                case "size":
                    sb.append(deque.size()).append("\n");
                    break;
                case "empty":
                    if(deque.isEmpty()) sb.append(1).append("\n");
                    else sb.append(0).append("\n");
                    break;
                case "front":
                    if(deque.isEmpty()) sb.append(-1).append("\n");
                    else sb.append(deque.peekFirst()).append("\n");
                    break;
                case "back":
                    if(deque.isEmpty()) sb.append(-1).append("\n");
                    else sb.append(deque.peekLast()).append("\n");
                    break;
            }
        }
        System.out.println(sb);
    }
}