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No, it wouldn't? What does a border guard know about calculus, much less some physicist's particular area of research? The whole reason this is farcical is that self-balancing search tree algorithms are notoriously based on multiple balancing cases and it's ridiculous to expect someone to have memorized them. Some even rely on amortized bounds which only complicates the implementation and explanation further.

[comex]

Even ignoring the border guard's competence, there's a difference between being able to solve problems and being able to solve problems after traveling for 23 hours straight - as @cyberomin said he had been. Maybe if it's pure recital from memory, something so basic that it should come to mind automatically without active thought (self-balancing trees are not even close), then I might trust myself to answer while sleep-deprived to that extent; but even then, I might easily make very stupid mistakes. If solving the problem requires even a bit of active intellectual effort, then forget about it; I'm too tired for that shit.