99클럽 코테 스터디 14일차 TIL - 백준(큐)

큐

Skill : Queue(Linkedlist)
큐의 메소드를 통해 값 구하기
queue.getLast() -> 다음과 같은 메소드를 통해 마지막 값 구할 수 있음.

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(br.readLine());
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        LinkedList<Integer> queue = new LinkedList<Integer>();
        for(int  i = 0; i<N; i++){
            StringTokenizer st = new StringTokenizer(br.readLine());
            String command = st.nextToken();
            if(command.equals("push")){
               queue.add(Integer.parseInt(st.nextToken()));
            }else if(command.equals("pop")){
                if(queue.isEmpty()){
                    bw.write("-1\n");
                }else{
                    bw.write(queue.remove()+"\n");
                }
            }else if(command.equals("size")){
                    bw.write(queue.size()+"\n");
            }else if(command.equals("empty")){
                if(queue.isEmpty()){
                    bw.write("1\n");
                }else{
                    bw.write("0\n");
                }
            }else if(command.equals("front")){
                if(queue.isEmpty()){
                    bw.write("-1\n");
                }else{
                    bw.write(queue.peek()+"\n");
                }

            }else if(command.equals("back")){
                if(queue.isEmpty()){
                    bw.write("-1\n");
                }else {
                    bw.write(queue.getLast()+"\n");
                }
            }

        }
        bw.flush();
        bw.close();

    }

}