[MrJohz]

While I didn't go with regexes per se, I did go with I think a fairly "standard" solution of iterating the string and finding matches, and got caught in the trap that a lot of people are mentioning.

In the end, I figured out a manual way around that, but then afterwards I realised that the iteration isn't really necessary given the problem at hand, and ended up going a completely different route that was a lot faster.

What surprised me is that I'd thought of the alternative at the start while reading the description, and then dismissed it because iteration is typically so convenient for these sorts of things.