There's also the fact that after giving the interview question for a while, you know what are the issues that candidates struggle with and can figure out how to help them.
If you're interviewing correctly, your job as an interviewer is to ensure that the candidate succeeds during the interview. For example, one question might require to check if two intervals overlap. There are multiple ways to check if they do. One can enumerate all possible ways that they can do (first interval fully contained within the second one, second interval partially overlapping with the first one, etc.) but this quickly grows into a complicated conditional. At that point, if the candidate struggles, you can mention "how would you check that two intervals don't overlap at all?" which is a much easier test that can then be inverted by the candidate.
What the interviewers should be looking for is if the candidate can think through a problem, can split it in smaller steps, can solve each step and is able to integrate each small step into a complete whole.
If you're interviewing correctly, your job as an interviewer is to ensure that the candidate succeeds during the interview. For example, one question might require to check if two intervals overlap. There are multiple ways to check if they do. One can enumerate all possible ways that they can do (first interval fully contained within the second one, second interval partially overlapping with the first one, etc.) but this quickly grows into a complicated conditional. At that point, if the candidate struggles, you can mention "how would you check that two intervals don't overlap at all?" which is a much easier test that can then be inverted by the candidate.
What the interviewers should be looking for is if the candidate can think through a problem, can split it in smaller steps, can solve each step and is able to integrate each small step into a complete whole.