마지막 두 원소

using System;

public class Solution {
    public int[] solution(int[] num_list) {
        int end = num_list.Length;
        int[] answer = new int[end+1];
        
        Array.Copy(num_list, answer, end);
        answer[end] = (num_list[end-1]>num_list[end-2]) ? num_list[end-1] - num_list[end-2] : num_list[end-1] * 2;
     
        return answer;
    }
}