public static LinkedList <T> Go(LinkedList <T> input)
{
var set = new HashSet <T>();
var current = input.Tail;
var retVal = new LinkedList <T>();
while (current != null)
{
if (!set.Contains(current.Val))
{
set.Add(current.Val);
retVal.Push(current.Val);
}
current = current.Next;
}
return(retVal);
}
