The interview process involved a technical phone screen, followed by onsite interviews.

I did not pass the phone interview. I wasn't expecting a system design question during the phone screen, so I was completely underprepared. This likely led to me "blowing" it.

Regarding the topological sort question, I attempted it from memory instead of consulting the Wikipedia algorithm, which proved to be a mistake. My code was probably overkill, and I didn't have a working version by the end of the phone interview.

I was applying for the full-stack position with an emphasis on back-end. For candidates applying with a front-end emphasis, they will likely ask domain-specific questions during the phone screen, so be prepared for that.

(System Design)

Describe how you would implement the view count on YouTube videos.

(Algorithms)

On Coderpad, implement topological sort. You may refer to Wikipedia, etc., for the algorithm.