The prompt was way longer than expected and took a few minutes just to parse what they were actually asking.
Clarify the definition of 'balanced' and the tree representation, then use a level-order traversal (BFS) to assign levels and compute subtree heights bottom-up to determine balance. Combine both tasks in a single post-order DFS or BFS pass to achieve O(n) time.
Pro tip: Explicitly state your assumptions about the balance definition and tree input format before coding, and mention that you'd validate with edge cases like a single node or a skewed tree.
Ask the interviewer to define 'balanced' (e.g., height-balanced with a threshold) and confirm the tree representation (e.g., nodes with left/right pointers).
Decide on BFS for levels and post-order DFS for balance, or a single post-order DFS that returns height and balance status while tracking depth.
For each node, compute the height of left and right subtrees, check the balance condition, and record the node's level (depth from root).
Write clean code with recursion or iteration, then walk through a small example and edge cases (empty tree, single node, skewed tree).
State that the solution runs in O(n) time and O(h) space for recursion stack, where h is tree height.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.