https://programmers.co.kr/learn/courses/30/lessons/12935

vector<int> solution(vector<int> arr) {
	vector<int> answer;
	if (arr.size() == 1) {
		answer.push_back(-1);
		return answer;
	}
	answer = arr;
	answer.erase(std::min_element(answer.begin(), answer.end()));
	return answer;
}