It's very easy to tell, but it doesn't make much difference. The best candidates have seen the problems before and don't even try to hide it, they just propose their solution right away.
I try give positive feedback for candidates who didn't know the problem but could make good use of hints, or had the right approach. But unfortunately, it's difficult to pass a Leetcode interview if you haven't seen a similar problem to what is asked before. Most candidates I interview nowadays seem to know all questions.
That's what the company has decided so we have to go along. The positive side is that if you do your part, you have good chances of being hired, even if you disagree with the process.
I try give positive feedback for candidates who didn't know the problem but could make good use of hints, or had the right approach. But unfortunately, it's difficult to pass a Leetcode interview if you haven't seen a similar problem to what is asked before. Most candidates I interview nowadays seem to know all questions.
That's what the company has decided so we have to go along. The positive side is that if you do your part, you have good chances of being hired, even if you disagree with the process.