Insert a whole linked list into other at k-th position

// A C# program to insert a linked list in
// to another linked list at position k
using System;

class GFG {

    // Structure for a linked list node /
    public class Node {
        public int data;
        public Node next;
    };

    // Function to insert whole linked list in
    // to another linked list at position k
    static Node insert(Node head1, Node head2,
                       int k)
    {
        // traverse the first linked list until k-th
        // point is reached
        int count = 1;
        Node curr = head1;
        while (count < k) {
            curr = curr.next;
            count++;
        }

        // backup next node of the k-th point
        Node temp = curr.next;

        // join second linked list at the kth point
        curr.next = head2;

        // traverse the second linked list till end
        while (head2.next != null)
            head2 = head2.next;

        // join the second part of the linked list
        // to the end
        head2.next = temp;
        return head1;
    }

    // Function to print linked list recursively
    static void printList(Node head)
    {
        if (head == null)
            return;

        // If head is not null, print current node
        // and recur for remaining list
        Console.Write(head.data + " ");
        printList(head.next);
    }

    // Given a reference (pointer to pointer) to the head
    // of a list and an int, insert a new node on the front
    // of the list.
    static Node push(Node head_ref, int new_data)
    {
        Node new_node = new Node();
        new_node.data = new_data;
        new_node.next = (head_ref);
        (head_ref) = new_node;
        return head_ref;
    }

    // Driven code
    public static void Main(String[] args)
    {
        // The constructed linked lists are :
        // a: 1.2.3.4.5;
        // b: 7.8.9.10.11
        Node a = null;
        Node b = null;
        int k = 2;

        // first linked list
        a = push(a, 5);
        a = push(a, 4);
        a = push(a, 3);
        a = push(a, 2);
        a = push(a, 1);

        // second linked list
        b = push(b, 11);
        b = push(b, 10);
        b = push(b, 9);
        b = push(b, 8);
        b = push(b, 7);

        printList(a);
        Console.WriteLine();

        printList(b);

        a = insert(a, b, k);

        Console.Write("\nResulting linked list\t");
        printList(a);
    }
}

// This code contributed by Rajput-Ji