Find Minimum in Linked List - 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 should the function return if the linked list is empty?
  • If the linked list is empty (head is None), the function should return None to indicate there are no values to compare.

P-lan

Plan the solution with appropriate visualizations and pseudocode.

General Idea: Traverse the linked list and find the minimum numeric value among the nodes.

1) Check if the linked list is empty; return `None` if true.
2) Initialize `min_val` with the value of the head node.
3) Traverse the linked list, comparing the value of each node with `min_val`.
4) If a node's value is less than `min_val`, update `min_val`.
5) Continue until the end of the list is reached.
6) Return `min_val` as the smallest value in the list.

⚠️ Common Mistakes

• Incorrectly initializing min_val, which could lead to incorrect comparisons or results.
• Not handling the case where the list might be empty, which should gracefully return None.

I-mplement

    def find_min(head):
        if not head:
            return None
        
        current = head
        min_val = head.value
        while current:
            if current.value < max_val:
                min_val = current.value
            current = current.next
        
        return min_val