One key thing they asked me in the interview was to solve the "Longest Substring Without Repeating Characters" problem. I started by clearly explaining the brute-force approach, then optimized it using the sliding window technique combined with a hashmap to achieve linear time complexity. This question was asked during the first technical round, right after my self-introduction. I was able to solve it within 15 minutes, handling all edge cases and clearly communicating my thought process. The interviewer appreciated my structured approach and clarity in explaining the solution.