HR call followed by a technical interview. The recruiter had either messaged the applicant via email or on LinkedIn. The technical phone screen was with an engineer familiar with a domain-relevant language to the role, but was from a different team. Make sure to get enough sleep before the phone screen.

In any language, write a simple calendar service that can:

1. Add an event.
2. Delete an event.
3. Get all events for a specific day.