The standard interview process was followed. The recruiter was great and moved quickly through the stages. This was followed by a chat with the hiring manager and some technical interviews. Some technical questions were harder than others. If you prepare properly using LeetCode, you should be able to pass the technicals.

If you were to design the mobile app of Google Calendar, what would you do?

Please talk from three aspects: server (including API), mobile client (iOS or Android), and UI design.

Frontend engineers may focus on the second part, but a basic understanding of the server side and UI design is required.