Contacted by a recruiter on LinkedIn for a contract position (remote).

First round: Self-serve coding, similar to LeetCode, featuring a dynamic programming question.

Second round: In-person coding using my language of choice (C++) on topics of sparse linear algebra and image processing.

Perhaps I am not used to this type of interview, but I found it a bit hard to communicate and understand how my solution needed to be delivered and what the given requirements were. The interviewer seemed to be distracted throughout the whole time, obviously switching between windows, which made it difficult to fully focus.

At the end, I could not answer how to further optimize my final solution, with only 2 minutes left.

I was ghosted by the recruiter afterwards. Even an automated reply would have been nicer.

Coding of sparse vector operations.

2D convolution, followed by optimization questions.

You need to know the underlying math for all and be ready to think fast.