It's ironic, given that algorithmic whiteboarding questions were developed as a reaction to '90s Microsoft "how do you move Mount Fuji" brain teasers. I would not call Leetcode questions puzzles in the same sense, yet many questions do require some foreknowledge of having seen the question to get to the optimal solution.

There could be an article or analysis written on that subject. What is the pedagogical gap between common CS education (both academic and not) and being able to intuitively leetcode? Students are learning the data structures and algorithms, but perhaps not in a way to approach problems in the same way that leetcode style platforms force them to really utilize that knowledge. Maybe there are problem-solving approaches not being covered?

A survey of the most commonly asked leetcode problems in industry would be illustrative as well. Some questions rely on advance knowledge that aren't really found in academic computer science. What CS course teaches two pointer - isn't that a competitive programming technique?