refactoring

The canonical multi-round build screen: a simple key-value store that grows new requirements every stage (TTL, transactions, scans). The signal is not stage 1, it is whether your code absorbs stage 4 without a rewrite. Here is how to design for it.

Google's 'vibe coding' screen: the spec is deliberately vague and changes mid-interview. The signal isn't the algorithm, it's whether you clarify before coding, structure for change, and keep tests green while the requirements move. Here is how to run that loop.