[2] 오픈 채팅방

#include <sstream>
#include <string>
#include <vector>
#include <map>

using namespace std;

vector<string> solution(vector<string> record) 
{
    vector<string> answer, state;
    map<string, string> user;

    for (int i = 0; i < record.size(); i++)
    {
        string str[3];
        string token;
        stringstream ss(record[i]);
        int index = 0;

        while (ss >> token)
                str[index++] = token;

        if (str[0] == "Enter")
        {
            state.push_back("님이 들어왔습니다.");
            answer.push_back(str[1]);
            user[str[1]] = str[2];
        }
        else if (str[0] == "Leave")
        {
            state.push_back("님이 나갔습니다.");
            answer.push_back(str[1]);
        }
        else
            user[str[1]] = str[2];
    }

    for (int i = 0; i < answer.size(); i++)
        answer[i] = user[answer[i]] + state[i];

    return answer;
}