There's some flowery language there about having a genuine desire to want to hire you unlike those 'other evil companies!'... sounds like the same shit pretty much every other company does to me.
I had one of our most senior engineers, who has worked in this language's compiler, to try to solve the exercise. Instead of 40 minutes, it took him three hours!
If a candidate is going to interview in a language, for the love of god, have as a prereq that the interviewer is actually capable of doing the exercise in that language.
Some orgs require only scripting, some go so far as to want application engineers who also know everything about AWS for devops/ops roles.
Disclaimer: I already asked via their google form for this information to be added in their docs.
Edited In Response To Parent Edit: Thanks for asking! We should definitely make it clearer if there are differences per role.
This is one commonly thrown BS regarding interviews. At the end of the day it is all about one-dimensional usual algorithmic questions.
Regarding LRU cache, I think this is one of less crazy interview questions. In one phone interview, I had to solve a DP problem, code it perfectly and pass all the test-cases on HackerRank in less than twenty minutes. I am not certain how many developers out there can pass such interviews without months of preparation in such situations. Tech interviews are basically programming contests. I am not against programming contests or algorithmic questions. But it seems the interview questions are getting crazier day by day.