insert_nth_ll.py

"""
Hackerrank solution.

Insert a node at a specific position in a linked list.
"""

def InsertNth(head, data, position):
    
    new_node = Node(data)
    count = 0
    
    if head is None:
        head = new_node
        return head

    elif position == 0:
        new_node.next = head
        head = new_node
        return head
    
    else:

        # 0 -> 1
        # 0 -> new -> 1
        # prev      cur

        curr = head
        prev = None

        while position > 0:
            prev = curr
            curr = curr.next
            position -= 1

        prev.next = new_node
        new_node.next = curr

        return head