A5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GerryTutor
{
    class Program
    {

        static List<int> NonRepeat(int[] arr)
        {
            HashSet<int> set = new HashSet<int>();
            foreach (var item in arr)
            {
                set.Add(item);
            }
            return set.ToList();
        }
        static void Main(string[] args)
        {
            int[] arr = { 8, 10, 31, 19, 8, 8, 31, 10 };

            List<int> l = NonRepeat(arr);
            foreach (var item in l)
            {
                Console.WriteLine(item);
            }
        }
    }
}