오픈채팅방 (2019 KAKAO BLIND RECRUITMENT)

원본 : https://programmers.co.kr/learn/courses/30/lessons/42888

코딩테스트 연습 - 오픈채팅방

 

풀이

import java.util.*;

class Solution {
    public String[] solution(String[] record) {
        Map<String, String> user = new HashMap<>();
        int cnt = 0;

        for (String str : record) {
            String[] strSplit = str.split(" ");
            if ("Enter".equals(strSplit[0])) {
                user.put(strSplit[1], strSplit[2]);
                cnt++;
            } else if ("Change".equals(strSplit[0])) {
                user.replace(strSplit[1], strSplit[2]);
            } else {
                cnt++;
            }
        }

        String[] answer = new String[cnt];
        int idx = 0;

        for (String str : record) {
            String[] strSplit = str.split(" ");
            if ("Enter".equals(strSplit[0])) {
                answer[idx++] = user.get(strSplit[1]) + "님이 들어왔습니다.";
            } else if ("Leave".equals(strSplit[0])) {
                answer[idx++] = user.get(strSplit[1]) + "님이 나갔습니다.";
            }
        }

        return answer;
    }
}