Insert a node at a specific position linked list

Problem Statement

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, an integer to add to the list and the position at which the integer must be inserted. Create a new node with the given integer, insert this node at the desired position and return the head node. A position of 0 indicates head, a position of 1 indicates one node away from the head and so on. 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, int position) method which takes three arguments - the head of the linked list, the integer to insert and the position at which the integer must be inserted. You should NOT read any input from stdin/console. position will always be between 0 and the number of the elements in the list (inclusive).

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

Sample Input

NULL, data = 3, position = 0 
3 --> NULL, data = 4, position = 0

Sample Output

3 --> NULL
4 --> 3 --> NULL

Explanation 
1. we have an empty list and position 0. 3 becomes head. 
2. 4 is added to position 0, hence 4 becomes head.

Note 
For the purpose of evaluation the list has been initialised with a node with data=2. Ignore it, this is done to avoid printing empty lists while comparing output.

Video lesson

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/*
  Insert Node at a given position in a linked list 
  head can be NULL 
  First element in the linked list is at position 0
  Node is defined as 
  struct Node
  {
     int data;
     struct Node *next;
  }
*/
Node* InsertNth(Node *head, int data, int position)
{
  // Complete this method only
  // Do not write main function. 
    int i;
    Node *newn = (struct Node*)malloc(sizeof(struct Node));
    newn -> data = data;
    if(position == 0)
        {
        newn -> next = head;
        head = newn ;
    }
    else
        {
        Node *tmp = head;
        for(i = 1 ; i < position ; i++)
            {
            tmp = tmp -> next ;
        }
        newn -> next = tmp -> next ;
        tmp -> next = newn ;
    }
    return head;
}