Yandex Machine Learning Engineer Intern interview questions

Yandex was the first company where I had interviewed, more than a year ago. In general, the interview process was not that encouraging, but based on other people's reviews, I knew how interviews are conducted at Yandex, so this was kind of expected. They gave me a medium LeetCode problem right away, and I stumbled a bit. It didn't work out very well; I made some mistakes in the code, but the interviewer said he was going to take some more time to ask me about ML (maybe to compensate for it). Turns out I wasn't really prepared for ML theory, so some questions I left with no answer; it didn't reflect well on me. Of course, I didn't make it to the next stage of the interview; the recruiter sent me feedback the day after.