InsertNodeAtHeadOfLinkedList.cs

// This challenge is part of a tutorial track by MyCodeSchool and is accompanied by a video lesson.

// You’re given the pointer to the head node of a linked list and an integer to add to the list. Create a new node with the given integer, insert this node at the head of the linked list and return the new head node. The head pointer given may be null meaning that the initial list is empty.

// Input Format 
// You have to complete the Node* Insert(Node* head, int data) method which takes two arguments - the head of the linked list and the integer to insert. You should NOT read any input from stdin/console.

// Output Format 
// Insert the new node at the head and return the head of the updated linked list. Do NOT print anything to stdout/console.

// Sample Input

// NULL , data = 1 
// 1 --> NULL , data = 2

// Sample Output

// 1 --> NULL
// 2 --> 1 --> NULL
// Explanation 
// 1. We have an empty list, on inserting 1, 1 becomes new head. 
// 2. We have a list with 1 as head, on inserting 2, 2 becomes the new head.

    /*
      Insert Node at the beginning of a linked list
      head pointer input could be NULL as well for empty list
      Node is defined as
      class Node {
         int Data;
         Node Next;
      }
    */
    // This is a "method-only" submission.
    // You only need to complete this method.

    public static Node Insert(Node head, int x)
    {
        var newNode = new Node();
        newNode.Data = x;        
        newNode.Next = head;
        head = newNode;
       
        return head;
    }