[BaekJoon] 28279번 덱2 문제 풀이 (Success)

28279번: 덱 2

 

☕Language: Java

 

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.ArrayDeque;
import java.util.StringTokenizer;
 
public class Main {
 
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
 
        int cnt = Integer.parseInt(br.readLine());
 
        ArrayDeque<Integer> deque = new ArrayDeque<>();
 
        StringBuilder sb = new StringBuilder();
 
        while (cnt-- > 0) {
            StringTokenizer st = new StringTokenizer(br.readLine(), " ");
 
            switch (st.nextToken()) {
            case "1":
                deque.addFirst(Integer.parseInt(st.nextToken()));
                break;
            case "2":
                deque.addLast(Integer.parseInt(st.nextToken()));
                break;
            case "7":
                if (!deque.isEmpty()) {
                    sb.append(deque.peekFirst() + "\n");
                } else {
                    sb.append("-1\n");
                }
                break;
            case "8":
                if (!deque.isEmpty()) {
                    sb.append(deque.peekLast() + "\n");
                } else {
                    sb.append("-1\n");
                }
                break;
            case "3":
                if (!deque.isEmpty()) {
                    sb.append(deque.peekFirst() + "\n");
                    deque.removeFirst();
                } else {
                    sb.append("-1\n");
                }
                break;
            case "4":
                if (!deque.isEmpty()) {
                    sb.append(deque.peekLast() + "\n");
                    deque.removeLast();
                } else {
                    sb.append("-1\n");
                }
                break;
            case "5":
                sb.append(deque.size() + "\n");
                break;
            case "6":
                sb.append((deque.isEmpty() ? "1" : "0") + "\n");
                break;
            }
 
        }
 
        bw.write(sb.toString());
 
        bw.flush();
        bw.close();
 
    }
 
}
 

🤔 해설

Deque: Double-Ended Queue

    - 큐의 양쪽으로 요소의 삽입과 삭제를 수행할 수 있는 자료구조

 

 

 

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