I recently attempted the first round of interviews, but I was not prepared enough and did not advance to further rounds. The interviewer was good and asked relevant technical questions appropriate for my knowledge level, mainly focused on C++.

1. OOPs concepts - What are the types of polymorphism, and write code to explain runtime polymorphism.

2. Questions on constructors and how they are invoked for inherited classes.

3. Virtual functions/abstract classes.

4. Binary tree question - View of a binary tree facing the root node.

5. High-level system design questions on WebSockets/HTTP, scaling, caching, etc.