Insert a node at a specific position in a linked list from hackerrank

Question

This is a hackerrank challege question and this is the link to the question https://www.hackerrank.com/challenges/insert-a-node-at-a-specific-position-in-a-linked-list/problem, though this question might have been answered here, I was hoping on solving it on my own and came close to doing so except for some issues which I stuck with.

This is my code

def insertNodeAtPosition(head, data, position):
 if position is 0:
 head = SinglyLinkedListNode(data, head)
 return
 count = 0
 while head:
 if count == position - 1:
 newNode = SinglyLinkedListNode(data)
 newNode.next = head.next
 head.next = newNode
 break
 head = head.next
 print(head.data)
 count +=1
 return head

It returns the correct result minus the elements before the position - 1 element e.g instead of 16 13 1 7, it returns 13 1 7 or instead of 1 2 3 4 5 7 6, it returns 5 7 6.

I am missing something but I cant seem to point it out. Please help me

Answer 1

Never mess with head when you deal with linked list. Please take a variable to head and use it to iterate.

my_iter = head

Then use this my_iter in all your loops.

Also your code for insert at zero returns a head without linking it to current zero.

• A.Sasori: Oh my God thanks alot that seems to be all that i was missing, my code passed all the test