[10546] 배부른 마라토너/ [프로그래머스] 완주하지 못한 선수

<백준>

#include <map>
#include <string>
#include <iostream>
#include <algorithm>
using namespace std;
map<string, int> m;
string str[100000];
string str1;
int main()
{
    int n,i;
    scanf("%d",&n);
    for(i = 0; i < n; i++) cin >> str[i], m[str[i]]++;
    for (i = 0; i < n - 1; i++) cin >> str1, m[str1]--;
    for (i = 0; i < n; i++)
	{
        if (m[str[i]] == 1)
		{
            cout << str[i];
            break;
        }
     }
}
<프로그래머스>

#include <iostream>
#include <string>
#include <vector>
#include <map>
using namespace std;
string solution(vector<string> participant, vector<string> completion)
{
	map <string, int> m;
	string answer = "";
	int i;
	for (i = 0; i < participant.size(); i++)
		m[participant[i]]++;
	for (i = 0; i < completion.size(); i++)
		m[completion[i]]--;
	for (i = 0; i < participant.size(); i++)
	{
		if (m[participant[i]] == 1)
			answer = participant[i];
	}
	return answer;
}