Finding remote freelance work: Toptal?

I'm trying to set myself up as a 100% remote developer, which - as someone who's traveled around a lot in the last few years, - is in some ways very easy (I'm already very mobile, I'm disciplined about working on my own), but in other ways is quite hard (I don't have an established network of existing remote-okay clients who I can plunder for ongoing work). My clients in Amsterdam have been great, but they've had the expectations of hiring a contractor, rather than a freelancer - that is to say they expected 9-5pm working from the office - of course fine if you live close-by, but not so good if you want to work flexibly and remotely.

As a result, I'm putting some work into getting listed as a Toptal developer, though it's quite tricky - you have to complete a challenging timed algorithm test before you take the serious interview. I attempted it a few years ago, completely unprepared for how hard it was, and totally failed (bummer). I'm going to retake it (they let you resit it after 6 months), and this time I'll be ready 💪🏻.

So, I've been practising the lessons on the Codality site (the programmer-testing website that Toptal uses to pre-screen candidates) as a sort of warm up. Though I feel this style of programming challenge doesn't necessarily correlate with someone's ability to build a good and stable iPhone app (it emphasises abstract problem solving), probably they're skills worth honing anyway. And it's pretty fun - like being set coursework back at Uni again.

Codality Lesson solutions: I'm posting on Github my solutions so far.