백준 1406번 에디터 [ Java ]

 

1406번: 에디터

처음엔 입력출력 때문에 시간 초과 나는줄 알았는데

스택을 사용한 더 빠른 풀이가 있었습니다..

 

틀린 코드

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        ArrayList<String> words = new ArrayList<>(Arrays.asList(bf.readLine().split("")));
        StringBuilder sb = new StringBuilder();
        int M = Integer.parseInt(bf.readLine());
        int cursor = words.size();
        for (int i = 0; i<M; i++){
            String[] input = bf.readLine().replaceAll(" ","").split("");
            if (input[0].equals("L"))
                cursor = cursor!=0 ? cursor-1 : 0;
            else if (input[0].equals("D"))
                cursor = cursor!=words.size() ? cursor+1 : cursor;
            else if (input[0].equals("B")) {
                if (cursor != 0) words.remove(--cursor);
            } else if (input[0].equals("P"))
                words.add(cursor++, input[1]);
        }
        for (String str : words) sb.append(str);
        System.out.print(sb);
    }
}

 

 

정답 코드

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Stack;
import java.util.StringTokenizer;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));
        Stack<String> left = new Stack<>();
        Stack<String> right = new Stack<>();
        Arrays.stream(bf.readLine().split("")).forEach(item -> left.push(item));
        int M = Integer.parseInt(bf.readLine());
        for (int i = 0; i<M; i++){
            StringTokenizer st = new StringTokenizer(bf.readLine());
            String input = st.nextToken();
            switch (input){
                case "L":
                    if (!left.isEmpty()) right.push(left.pop());
                    break;
                case "D":
                    if (!right.isEmpty()) left.push(right.pop());
                    break;
                case "B":
                    if (!left.isEmpty()) left.pop();
                    break;
                case "P":
                    left.push(st.nextToken());
                    break;
            }
        }
        StringBuilder sb = new StringBuilder();
        left.forEach(item->sb.append(item));
        while (!right.isEmpty()) sb.append(right.pop());
        System.out.print(sb);
    }
}