How to find nth element from the end of a singly linked list?

Question

The following function is trying to find the nth to last element of a singly linked list.

For example:

If the elements are

Answer 1

Solution in C#. Create a LinkedList with dummy values.

  LinkedList ll = new LinkedList();
            ll.AddFirst(10);
            ll.AddLast(12);
            ll.AddLast(2);
            ll.AddLast(8);
            ll.AddLast(9);
            ll.AddLast(22);
            ll.AddLast(17);
            ll.AddLast(19);
            ll.AddLast(20);

Create 2 pointers p1 & p1 which point to the First Node.

        private static bool ReturnKthElement(LinkedList ll, int k)
        {
            LinkedListNode p1 = ll.First;
            LinkedListNode p2 = ll.First;

Iterate through the loop till either p2 is null - which means linkedlist length is less than Kth element OR till the Kth element

            for (int i = 0; i < k; i++)
            {
                p2 = p2.Next;
                if (p2 == null)
                {
                    Console.WriteLine($"Linkedlist is smaller than {k}th Element");
                    return false;
                }
            }

Now, iterate both the pointers till p2 is null. Value containted in p1 pointer will correspond to Kth Element

            while (p2 != null)
            {
                p1 = p1.Next;
                p2 = p2.Next;
            }
            //p1 is the Kth Element
            Console.WriteLine($"Kth element is {p1.Value}");
            return true;
        }