Since it's "quite deep" and you might have spent hours looking for a solution on the Web, why would you ask this question to a candidate in a 45 min interview? Do you think it's fair? And how would you define success since everyone would fail on this question? Just curious...
I've been interviewed many many times in my career. I switched jobs about 7 times always going through the standard hiring process. Looking for better opportunities and higher challenges. So, this is based on my knowledge and experience I'd say. It's subjective indeed, but I've interviewed candidates as well from junior to staff and I know when an interviewer is happy or not. Still subjective though.
prestigious = Google/FB etc.
Most of the questions I get lead to a "you know it" or "you don't know it" kind of answers. If you know it then you explain how it works. If not, I personally consider that a failure. Sometimes we go into edge cases, same scenario... you know when you give the right answer or if you doubt then it's a failure. In terms of coding challenges on a shared code collaboration tool, I would say that I come up with a working solution, on time, using a great approach. I might have failed one or 2 coding challenges (fail = needed a tip to move forward), but I knew right away I wouldn't count on these interviews. Some interviewers would verbally approve my solution, some would simply move on to the next question.
From what I've been doing in the past, this would easily move the process to the next step or onsite interview.