8주차. 10866 덱

10866. 

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

10866번: 덱

📌문제

- 예제1

  📝입력

 

15
push_back 1
push_front 2
front
back
size
empty
pop_front
pop_back
pop_front
size
empty
pop_back
push_front 3
empty
front

  💻출력

 

2
1
2
0
2
1
-1
0
1
-1
0
3

📌풀이
216ms, 18588kb

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 Deque_10866 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        StringBuilder sb = new StringBuilder();
        Deque<Integer> deque = new LinkedList<>();
        int n = Integer.parseInt(br.readLine());

        for(int i = 0; i < n; i++){
            st = new StringTokenizer(br.readLine());
            String command = st.nextToken();
            if(command.equals("push_front")){
                int tmp = Integer.parseInt(st.nextToken());
                deque.addFirst(tmp);
            }
            else if(command.equals("push_back")){
                int tmp = Integer.parseInt(st.nextToken());
                deque.addLast(tmp);
            }
            else if(command.equals("pop_front")){
                int num = deque.isEmpty() ? -1 : deque.pollFirst();
                sb.append(num).append("\n");
            }
            else if(command.equals("pop_back")){
                int num = deque.isEmpty() ? -1 : deque.pollLast();
                sb.append(num).append("\n");
            }
            else if(command.equals("size")){
                sb.append(deque.size()).append("\n");
            }
            else if(command.equals("empty")){
                int num = deque.isEmpty() ? 1 : 0;
                sb.append(num).append("\n");
            }
            else if(command.equals("front")){
                int num = deque.isEmpty() ? -1 : deque.peekFirst();
                sb.append(num).append("\n");
            }
            else if(command.equals("back")){
                int num = deque.isEmpty() ? -1 : deque.peekLast();
                sb.append(num).append("\n");
            }
        }

        System.out.print(sb);

    }
}

 

자바에서 제공해주는 deque를 활용해서 풀었음