> Competence is a spectrum and so at some level of competence there will be people who are competent but unable to pass overly complex interview questions
Competence is most absolutely not one spectrum. Competence is measured in dozens (hundreds, really) different axis. Everyone will have different scores (if we could realiably narrow it to a score, which we can't) on different axis of skills. Which of the skill axis are most relevant for any given role will vary, obviously. A generalist will have decent scores in many, a specialist may have mediocre scores in many but 99+percentile in their chosen areas.
Leetcode interviewing measures along one single uninteresting axis, the one corresponding to memorization of algorithm puzzles. That axis happens to be entirely irrelevant to any job I've ever hired for. So I don't test for that because I care as much for your skill doing leetcode as I care for your skill juggling frogs. Neither is relevant to the job.
Have you considered that with a strong understanding of elementary algorithms and data structures it is possible "solve" rather than "memorize" these algorithm puzzles?
In the interview format it is most certainly not possible. It is a dance where both sides pretend that the interviewee is going to invent, in ~30 minutes, under intense interview stress, on a whiteboard, some algorithm that took usually years of research to originally develop.
If that were even remotely possible, why isn't that person cranking out multiple novel algorithm research papers per day? They should be outpublishing Knuth, for sure.
So, no. The only road is to memorize extensively and practice acting skills on the delivery.
Most leetcode problems I have seen are not research problem statements and usually require applying one or two algorithms taught in any CS program. So I have to disagree.
EDIT: Obviously even some of the most elementary Algo 101 problems were research questions at some point, and led to published papers, but that's the reason people write textbooks and use them in college, so newcomers don't have to redo the foundational work.
Competence is most absolutely not one spectrum. Competence is measured in dozens (hundreds, really) different axis. Everyone will have different scores (if we could realiably narrow it to a score, which we can't) on different axis of skills. Which of the skill axis are most relevant for any given role will vary, obviously. A generalist will have decent scores in many, a specialist may have mediocre scores in many but 99+percentile in their chosen areas.
Leetcode interviewing measures along one single uninteresting axis, the one corresponding to memorization of algorithm puzzles. That axis happens to be entirely irrelevant to any job I've ever hired for. So I don't test for that because I care as much for your skill doing leetcode as I care for your skill juggling frogs. Neither is relevant to the job.