[BOJ 10866] 덱 (java)

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

문제 풀이

package basics_200;

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

public class BOJ10866 {

	public static void main(String[] args) throws NumberFormatException, IOException {
		// TODO Auto-generated method stub
		
		//자바에서의 덱 선언 
		Deque<Integer> deque = new ArrayDeque<>();
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		// 테스트케이스
		Integer tc = Integer.parseInt(br.readLine());
		
		while(tc>0) {
			String s = br.readLine();
			String[] array = s.split(" "); 
			switch(array[0]) {
			case "push_front":
				deque.offerFirst(Integer.parseInt(array[1]));
				break;
			case "push_back":
				deque.offerLast(Integer.parseInt(array[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(0);
				}else {
					System.out.println(1);
				}
				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;
			}
			tc--;
		}

	}

}