Phone interview :
I've had my phone interview with bloomberg two weeks ago. The interviewer was really nice and started the interview with questions as : Introduce yourself - Why Bloomberg - Talk about a certain experience .... Then we went on to hackerrank. The first 10 mins were general OOP design questions as:
1 - What is new in c++.
2 - What happens if we don't delete
3 - Usage of unique_ptr and shared_ptr
4 - Virtual functions ...

	Then the main problem was : https://leetcode.com/problems/design-underground-system/
	

I received an email two days later saying that I passed to the first onsite.

1st Onsite:
Two interviewers. First 10 mins is an introduction as that in the phone interview. Then went into hackerrank. The problem was similar to https://leetcode.com/problems/merge-intervals/submissions/
They also asked to write some test cases as well. They were also picky about the naming of the class and the functions and such stuff, as they want them to be as meaningful as possible. Still waiting for an answer, expecting to move on the 2nd onsite interview.

Any idea how should I start practicing for a system design interview, knowing that the application is a new grad one?