Codepath

Get Tail

Unit 5 Session 2 (Click for link to problem statements)

U-nderstand

Understand what the interviewer is asking for by using test cases and questions about the problem.

  • How do we handle finding the tail in a single-node list?
    • If the list has only one node (head), that node is both the head and the tail, so we return its value.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Traverse the linked list starting from the head until reaching the last node, and return its value as the tail.

1) Check if the list is empty (`head` is `None`). If it is, return `None`. 2) Initialize a variable `current` to `head` to start traversal. 3) Use a loop to navigate through the list until reaching the last node (where `current.next` is `None`). 4) Return the value of `current` as the value of the tail node.

⚠️ Common Mistakes

  • Neglecting to handle the edge case where the list is empty, which should promptly return None.
  • Incorrectly navigating through the list or stopping the traversal prematurely.

I-mplement

def get_tail(head): if not head: return None current = head while current.next: current = current.next return current.value 
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