백준 10866번 - 덱 (Java 8)

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

10866번: 덱

 

Deque, LinkedList 사용

import java.io.*;
import java.util.Deque;
import java.util.LinkedList;
import java.util.StringTokenizer;

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


        for(int i=0; i<N; i++){
            st= new StringTokenizer(br.readLine());
            executeCommand();
        }
    }
    public static void executeCommand(){
        switch (st.nextToken()){
            case "push_front":
                push_front();
                break;
            case "push_back":
                push_back();
                break;
            case "pop_front" :
                pop_front();
                break;
            case "pop_back":
                pop_back();
                break;
            case "size":
                size();
                break;
            case "empty":
                empty();
                break;
            case "front":
                front();
                break;
            case "back":
                back();
                break;
        }
    }

    public static void push_front(){
        deque.offerFirst(Integer.parseInt(st.nextToken()));
    }
    public  static void push_back(){
        deque.offerLast(Integer.parseInt(st.nextToken()));
    }
    public static void pop_front(){
        if(deque.isEmpty()){
            System.out.println(-1);
        } else{
            System.out.println(deque.pollFirst());
        }
    }
    public static void pop_back() {
        if(deque.isEmpty()){
            System.out.println(-1);
        } else{
            System.out.println(deque.pollLast());
        }
    }
    public static void size(){
        System.out.println(deque.size());
    }

    public static void empty() {
        if(deque.isEmpty()){
            System.out.println(1);
        }else{
            System.out.println(0);
        }
    }
    public static void front(){
        if(deque.isEmpty()){
            System.out.println(-1);
        }else{
            System.out.println(deque.peekFirst());
        }
    }
    public static void back(){
        if(deque.isEmpty()){
            System.out.println(-1);
        }else{
            System.out.println(deque.peekLast());
        }
    }
}

구현체에 ArrayDeque,ConcurrentLinkedDeque, LinkedBlockingDeque, LinkedList 등이 있다고 한다.