On Codeforces Round #819: my grumbling and my screencast

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Today I participated in Codeforces Round 819 (Div. 1 + Div. 2) and Grimoire of Code Annual Contest 2022. At first glance, this was really a nice contest, and even though some problems were a bit too technical, they did contain some certain ideas (and as to whether these ideas were cool and beautiful, I guess there's no accounting for taste). However, the tests in the harder problems weren't strong enough. For example,

I easily uphacked nikgaevoy's solution 171150224 of 1726F - Late For Work (submissions are not allowed), where he printed negative numbers on tests as little as with $$$n=2$$$; (btw, congrats nikgaevoy on becoming an IGM!)
heno239 uphacked turmax's solution 171126442 of 1726G - A Certain Magical Party with also a tiny test; (btw, congrats turmax on becoming an LGM!)

Nevertheless, I screencast the solving process (with my struggling to solve 1726F - Late For Work (submissions are not allowed)) and explanation of problems A–F, and I am now uploading it to YouTube, the video should appear here in several hours. Please leave your feedback (and other cases of high- or low-quality testing in this contest) in the comments!