Design a parking lot system.
Whether you can turn a vague brief into a clean object model and resist inventing requirements.
System designWarm-up
What a strong answer does
This is an object-modelling question wearing a systems-design costume, and the commonest failure mode is to start designing distributed services, caches, sharded databases, or license-plate recognition pipelines. The useful first move is to narrow the problem: what must the parking lot actually do? At minimum, it should accept an entering vehicle, assign it an appropriate space, remember that assignment, and later compute the fee and release the space when the vehicle exits.