Replace Node - codepath/compsci_guides GitHub Wiki

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.

• What happens if the original value is not found in any node?
  • The function will traverse the entire list without making any changes, leaving the linked list unchanged.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Traverse the linked list from the head, checking each node's value and replacing it if it matches the original value.

1) Start at the `head` of the linked list.
2) Traverse through the list using a loop, checking each node's value.
3) If a node's value matches `original`, update it to `replacement`.
4) Continue until all nodes have been checked (i.e., until the end of the list).

⚠️ Common Mistakes

• Failing to handle cases where the list is empty (i.e., head is None).
• Not correctly updating the node value or missing nodes due to incorrect loop conditions.

I-mplement

def ll_replace(head, original, replacement):
  current = head
  while current:
    if current.value == original:
      current.value = replacement
    current = current.next