The process with the recruiter was very smooth (no call, only email).

Tech screening - the worst experience I have had to date:

• I asked clarifying questions on the input. The interviewer (probably unintentionally) misled me, thus I had a different algorithm than what was needed.
• Sample inputs were bad and unclear on input format. This added to the wrong clarification from the previous point (the same input would apply to multiple questions, likely the interviewer got this from a different question).
• The interviewer was in his kitchen with the video on (totally fine). However, another person frequented the video and peered into the screen often. They had side conversations with the other person, with the mic on, which was very distracting to know if they were talking to me.
• I implemented the solution for my understanding of the question and discussed its complexity. Only then did he say that my understanding was different from what he wanted.
• With 15 minutes left, I was trying to implement the new algorithm, and the interviewer insisted that I use a particular data structure ONLY.
• The interviewer did not know what a "post-increment operator" is.

LeetCode hard question related to arrays and trees.

The question itself is not on LeetCode, but would be classified as hard.