The process consisted of:

• Two recruiter interviews
• A HackerRank coding challenge
• Four live coding sessions
• One manager session

Candidates could schedule as many recruiter feedback sessions as they desired in between.

Overall, it was a challenging process for a junior, requiring significant effort to catch up between sessions and prepare for the next. It was quite exhaustive.

For the concurrency part, I was implementing a callback system that saves callbacks and executes them after a certain event. For data structures, I was implementing a set using a map and an array as the underlying structure. For algorithms, it was a perfect binary tree, updating nodes. For system design, it was nothing like what you'd find online but a simple implementation of a library. Other people here mentioned all the questions in even more detail. Had I read them before, I would have aced all the live sessions. They didn't change the questions at all.