Well it shows that you are ready to invest a lot of your own free time into being recruited there - i.e. you'll be a loyal and hard worker. And that you're smart enough to learn it all. So I would say it has a character + IQ component to it.

Of course 95%+ of it will usually be useless in your real-life work, to solve most of those problems in the time given you need to know the problem and the optimal solution to it so basically memorization with little thinking.