Those algorithm test platforms are completely useless. I stopped using them long ago. No engineer I hire has to sort shit or filter out duplicates. I assume they know the sort functions in the language. I ask engineers with a blank GitHub to implement a small demo project which shouldn't take longer than 2-3h to finish and they have 2 weeks time (or actually as long as they need) to deliver. It gives me a lot of insight, I can see how people structure their code and if the code looks sloppy etc. You don't get a normal day at work result if you put people under pressure with these pseudo-hacker platforms. Most of the candidates have a life and I don't expect them to spend their evenings on some platform to impress potential new employers.