Amazon Interview Experience | Set 353 (For SDE-2)

I went through some interview rounds for SDE-2 in amazon. Below is the format.
Round1:

1. LCA of Binary tree
2. Finding minimum cost to combine n pipes of different size.

Round2:

1. Behavioural question.
2. Design Dating application. HLD, then specific discussion of profile search and ranking based on the users’ interest. Discussion on making it scalable.

Round3:

1. Design cricket score board.

Round4:

1. Architecture of current project.
2. Design an aggregator service that would be serving various services to a lot of clients. Discussion on how this service can hand billions of data in a request. Code for the service.