[백준] 자바 문제 풀이 5430 : 골드5

BOJ 5430 : AC

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

public class Main {
    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        StringTokenizer st;

        int test_case = Integer.parseInt(br.readLine());

        for(int i = 0; i < test_case; i++) {
            boolean reverse = false;
            boolean error = false;
            String func = br.readLine();
            int n = Integer.parseInt(br.readLine());

            st = new StringTokenizer(br.readLine(), "[],");
            Deque<String> dq = new ArrayDeque<>();
            for(int k = 0; k < n; k++) {
                dq.offer(st.nextToken());
            }

            for(int k = 0; k < func.length(); k++) {
                if(func.charAt(k) == 'R'){
                    reverse = !reverse;
                } else {
                    if(dq.isEmpty()) {
                        error = true;
                        break;
                    }
                    else if(reverse)
                        dq.removeLast();
                    else
                        dq.removeFirst();
                }
            }

            if(error) {
                bw.write("error\n");
            } else {
                if(dq.isEmpty()) {
                    bw.write("[]\n");
                } else {
                   StringBuilder sb = new StringBuilder("[");
                    if (reverse) {
                        sb.append(dq.removeLast());
                        while (!dq.isEmpty()) {
                            sb.append("," + dq.removeLast());
                        }
                    } else {
                        sb.append(dq.removeFirst());
                        while (!dq.isEmpty()) {
                            sb.append("," + dq.removeFirst());
                        }
                    }
                    sb.append("]\n");
                    bw.write(sb.toString());
                }
            }
            bw.flush();
        }
        bw.close();
        br.close();
    }
}