[2019 KAKAO] 42888 : 오픈채팅방

#include <string>
#include <vector>
#include <unordered_map>
#include <sstream>

using namespace std;

vector<string> solution(vector<string> record) {
    vector<string> answer;
    unordered_map<string,string> idMap;
    
    for(vector<string>::iterator iter = record.begin(); iter != record.end(); iter++)
    {
        stringstream ss(*iter);
        string cmd, id, name;
        ss >> cmd;
        if(cmd.compare("Enter") == 0)
        {
            ss >> id >> name;
            idMap[id] = name;
        } 
        else if(cmd.compare("Change") == 0)
        {
            ss >> id >> name;
            idMap[id] = name;
        }
    }
    
    for(vector<string>::iterator iter = record.begin(); iter != record.end(); iter++)
    {
        stringstream ss(*iter);
        string cmd, id;
        ss >> cmd;
        if(cmd.compare("Enter") == 0)
        {
            ss >> id;
            answer.push_back(idMap[id] + "님이 들어왔습니다.");
        } 
        else if(cmd.compare("Leave") == 0)
        {
            ss >> id;
            answer.push_back(idMap[id] + "님이 나갔습니다.");
        }
    }
    
    return answer;
}