I was thrown a Leetcode hard question in the last round of a long tiring on-site. I gave a solution which meets the optimal time/space complexity, but the interviewer was wrong with his analysis, I politely explained everything and he agreed that's a valid solution, it took some time so there wasn't much time left. "OK, let's code" When I was about to write the first line... "You know what? I think this approach is too easy for you to code, can you use a different approach so that we know you can write tricky code" And a winning smile. Call it a stress test or whatever, hire a robot.