They give you a HackerRank test (4 questions in 1 hour 15 minutes), then the HR calls you. After that, there is the live coding session, where two programmers watch you code while on call.

The code doesn't have to compile; they are only interested in the algorithm.

I received an easy question, but as I hadn't solved any problems of this type before, I couldn't provide the most optimal solution, only a brute-force one. I think you either get lucky by knowing the problem type, learn a lot of algorithms, or are a genius and come up with a solution on the spot.

It's also hard to think on the spot while knowing two others are on the line.

Given the following list of objects {user, loginTime, logoutTime}. What is the maximum number of concurrent users logged in at the same time?

Input: [ {user: A, login: 1, logout: 3}, {user: B, login: 3, logout: 4}, {user: C, login: 1, logout: 2}, {user: D, login: 123123123, logout: 987987987}, {user: E, login: 1, logout: 3} ]

Output: 3