Greatest Node

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 should the function behave if the linked list is empty?
  • If the list is empty (head is None), the function should return None as there are no values to compare.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Traverse the linked list, comparing each node's value to the current maximum, updating the maximum value as needed.

1) If the list is empty (`head` is `None`), return `None`.
2) Initialize `max_val` with the value of the head node, assuming the list is non-empty.
3) Traverse the linked list starting from the head:
   - Compare the value of each node with `max_val`.
   - If a node's value is greater than `max_val`, update `max_val` to this new higher value.
4) After traversing all nodes, return `max_val` as the maximum value found.

⚠️ Common Mistakes

• Forgetting to handle the empty list scenario, which would lead to errors when trying to access head.value.
• Not properly initializing max_val, potentially leading to incorrect results if not set to the head's value initially.

I-mplement

    def find_max(head):
        if not head:
            return None
        
        current = head
        max_val = head.value
        while current:
            if current.value > max_val:
                max_val = current.value
            current = current.next
        
        return max_val