45 삐약 : 백준 10866| 덱 [바킹독 문제 풀이|Deque|JAVA]

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

10866번: 덱

 

 

package BKD_0x7_Deque;

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

public class BOJ_10866 {
    public static void main(String[] args) throws IOException {
        Deque<String> deque = new LinkedList<>();

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

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

        for(int i=0;i<N;i++){
            String input[] = br.readLine().split(" ");

            switch (input[0]){
                case "push_front":
                    deque.addFirst(input[1]);
                    break;
                case "push_back":
                    deque.addLast(input[1]);
                    break;
                case "pop_front":
                    if(!deque.isEmpty()) System.out.println(deque.pollFirst());
                    else System.out.println(-1);
                    break;
                case "pop_back":
                    if(!deque.isEmpty()) System.out.println(deque.pollLast());
                    else System.out.println(-1);
                    break;
                case "size":
                    System.out.println(deque.size());
                    break;
                case "empty":
                    if(deque.isEmpty()) System.out.println(1);
                    else System.out.println(0);
                    break;
                case "front":
                    if(!deque.isEmpty()) System.out.println(deque.peekFirst());
                    else System.out.println(-1);
                    break;
                case "back":
                    if(!deque.isEmpty()) System.out.println(deque.peekLast());
                    else System.out.println(-1);
                    break;

            }
        }


    }
}