I had two system design rounds and one LLD round. I didn't hear back from HR after LLD; it didn't go as well as I would have wanted. The LLD interviewer was cold and distant and barely responding to whatever I was saying, so it was a bit frustrating.

1. Design a web crawler.
2. Design a user service CRUD that can support 500 RPS at 1-2ms response times.
3. LLD for a calendar application:

• Ability to create, update, and delete an Event. An event would typically consist of {start, end, location, Owner, participant-list, title}. Events can either be like meetings (with a dedicated location and appropriate guest-list) or as well be like holidays, meetings, reminders, etc. An event, once created, can be either accepted or rejected by the constituent users; if neither, it should be in a neutral state.
• Get Calendar for a user UI weekly, monthly, and daily.
• Get Event details.
• For a given set of users [U1, U2,....Un], identify a common free slot of time.