Algorithm, programmers, 카카오2020(오픈채팅방-42888)

package org.programmers;
import java.util.ArrayList;
import java.util.HashMap;
public class kakao_2020_openchat {
	public static void main(String[] args) {
		String[] record = {
				"Enter uid1234 Muzi",
				"Enter uid4567 Prodo",
				"Leave uid1234",
				"Enter uid1234 Prodo",
				"Change uid4567 Ryan"
		};
		solution(record);
	}
	public static String[] solution(String[] record) {
		ArrayList<String> answer = new ArrayList<String>();
		HashMap<String, String> user = new HashMap<>();
		for (int i=0; i<record.length; i++) {
			String[] splitRecord = record[i].split(" ");
			// 명령문 비교
			switch (splitRecord[0]) {
			//아이디, 닉네임
			case "Enter" :
				//if ( !user.containsKey(splitRecord[1]) )
				user.put(splitRecord[1], splitRecord[2]);
				break;
			case "Change" :
				user.put(splitRecord[1], splitRecord[2]); break;
			}
		}
		for (int i=0; i<record.length; i++) {
			String[] splitRecord = record[i].split(" ");
			String nickName = user.get( splitRecord[1] );
			switch (splitRecord[0]) {
			case "Enter" :
				answer.add(nickName+"님이 들어왔습니다."); break;
			case "Leave" :
				answer.add(nickName+"님이 나갔습니다."); break;
			}}
		String[] array = new String[answer.size()];
		for (int i=0; i<answer.size(); i++)
			array[i] = answer.get(i);
		return array;
	}
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class Solution {
 public String[] solution(String[] record) {
 HashMap<String, String> codeMap = new HashMap<String, String>();
 codeMap.put("enter","들어왔습니다.");
 codeMap.put("leave","나갔습니다.");
 HashMap<String, String> uidMap = new HashMap<String, String>();
 List<String> list = new ArrayList<String>();
 for(String str:record){
 String[] split = str.split("\\s+");
 String code = split[0];
 String uid = split[1];
 if(split.length > 2) {
 String name = split[2];
 uidMap.put(uid, name);
 }
 if(!"Change".equalsIgnoreCase(code)){
 list.add(code +" "+uid);
 }
 }
 String[] answer = new String[list.size()];
 for(int i=0;i<answer.length;i++){
 String[] split = list.get(i).split("\\s+");
 String name = uidMap.get(split[1]);
 answer[i] = name+"님이 "+ codeMap.get(split[0].toLowerCase());
 }
 return answer;
 }
}