Python data engineering interview problem. Difficulty: intermediate. Pattern: Linked Lists. About 14 minutes. Part of the Pro drill bank.
Return the middle node's value (second middle if even length). Treat this as a production helper: match the contracted return shape, including empty and duplicate inputs.
Implement middle_node(values: list) returning the middle value of the list API linked list. For even length, return the second middle. ; [1, 2, 3, 4, 5, 6] → 4.
Input: middle_node([1, 2, 3, 4, 5]) Output: 3 Odd length middle.
Topics: lakebench, python, middle, two pointers.
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Interview-style drill: Return the middle node's value (second middle if even length).
Implement `middle_node(values: list)` returning the middle value of the list API linked list. For even length, return the second middle. Example: `[1, 2, 3, 4, 5]` → `3`; `[1, 2, 3, 4, 5, 6]` → `4`. Keep the harness.