NDA Software Engineer interview questions

TL;DR: Extremely challenging, but super educational. There was no chance of passing technical interviews without deep preparation (classic HFT, no surprises there). Yet, despite the rejection, I was pleased with the process. At the very first stage, the recruiter dedicated significant time to presenting the company and teams, although a full picture wasn't quite clear because of NDA. A plus: the company fully covers relocation. During the subsequent technical round, my performance wasn't my best. However, the interviewer offered guiding questions, so the conversation was rather smooth. At the end, he allocated time to explain a more optimal solution to a problem I had struggled with and answered my questions, despite us running over time. A particularly pleasant surprise was the feedback after the interview: it was swift, arriving literally the next day, and detailed. It highlighted what I did well and pinpointed specific areas for growth, enumerating concrete topics for deeper study. The cherry on top? They even recommended preparation materials. Will probably make another try in a year or so.