백준 5430번 AC [ Java ]

5430번: AC

reverse 연산 시간을 줄이기 위해서 커서를 두었습니다.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int T = Integer.parseInt(br.readLine());
        StringBuilder sb = new StringBuilder();
        for (int i=0; i<T; i++){
            boolean error = false, cursor = false; // false : front, true : back
            String[] fn = br.readLine().split("");
            br.readLine();
            String input = br.readLine();
            ArrayList<String> list = new ArrayList<>(Arrays.asList(input.substring(1, input.length()-1).split(",")));
            if (list.get(0).equals("")) list.remove(0);
            for (String f : fn){
                switch (f){
                    case "R": cursor = !cursor; break;
                    case "D":
                        if (list.size()==0) {
                            error = true;
                            break;
                        } else if (cursor) list.remove(list.size()-1);
                        else list.remove(0);
                }
            }
            if (cursor) Collections.reverse(list);
            sb.append(error ? "error\n" : "["+String.join(",", list)+"]\n");
        }
        System.out.print(sb);
    }
}