If a good candidate can do it in 3 weeks, then a middling one can do it in 10 weeks, and a bad one in 6 months of memorizing. They all pass the screen, but two

If a good candidate can do it in 3 weeks, then a middling one can do it in 10 weeks, and a bad one in 6 months of memorizing. They all pass the screen, but two are lower-quality, and the bad candidate is about as much of a waste of the "real" interview as a total fraud would be. If the bar is that low, just use an accredited degree, certification, references, or a proctored quiz with questions like "define a linked list in < 3 sentences," and it would be just as effective at filtering the very lowest, while more pleasant for everyone involved and maybe cheaper. Crammable puzzles that don't represent real software engineering don't provide much more value than those filters would.