[Level 1][C++] 완주하지 못한 선수

#include <string>
#include <vector>
#include <algorithm>

using namespace std;

string solution(vector<string> participant, vector<string> completion) {

    string answer;
    
    sort(participant.begin(), participant.end());
    sort(completion.begin(), completion.end());
    
    for(int i=0; i<completion.size(); i++)
        if(participant[i].compare(completion[i]) != 0)
        {
            answer = participant[i];
            return answer;
        }
    
    return participant[participant.size()-1];  
}