[백준] 7785번 회사에 있는 사람 문제! (silver 5

import java.io.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.StringTokenizer;
public class Main{
    public static void main(String[] args) throws IOException {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(System.out));
        HashMap<String, Integer> people=new HashMap<>();
        StringTokenizer st;
        int n=Integer.parseInt(br.readLine());
        for(int i=0; i<n; i++){
            st=new StringTokenizer(br.readLine());
            String name=st.nextToken();
            String status=st.nextToken();

            if(status.equals("leave")){
                people.remove(name);
            }
            else{
                people.put(name,1);

            }
        }
        ArrayList<String> peopleStatus=new ArrayList<>(people.keySet());
        Collections.sort(peopleStatus);
        for(int i=peopleStatus.size()-1; i>=0; i--){
            bw.write(peopleStatus.get(i)+"\n");
        }
        bw.flush();

    }
}