Pinterest Sr. Machine Learning Engineer interview questions

Had an initial HR screen for 30 mins and then invited to a 60 minute technical phone screening interview. No one showed up for the technical interview and due to poor HR management, no HR rep was able to help when I reached out. Got a response a day later that the meeting was moved to a week later due to miscommunication between their EU & US offices. A week later, the technical interviewer focused more on topics unrelated to your previous work rather than discussing the projects you had been involved in. Typical ML questions were asked in the technical interview, e.g. what is L1/L2 regularisation (make sure to you know the math behind why L1 leads to feature sparsity vs L2 (derivation etc.)), vanishing gradient problem (what kind of activation functions can mitigate this etc.). Finally, a leet-code medium question to end of the session. I was able to finish the solution but not enough time to debug edge cases. Got an automatic rejection 2 days later.

Brief introduction and then started coding. Overall process is focusing on solving the corner cases of this question. And it's not easy to come up with and solve all corner cases.