Their speedup from the initial code to the end of the map blogpost is ~5%. In their repo, they have a much better version that presumably there will eventually

Their speedup from the initial code to the end of the map blogpost is ~5%. In their repo, they have a much better version that presumably there will eventually be blogposts leading up to. That version is approximately twice as fast as their initial version. I worked on optimizing that version for a little while. The result is a version which takes 30% of the time of the original and a little worse than twice as fast as the best in the repo. That's still disappointingly slow to me, but I'm not great at c++ so I don't really want to take the time to try to improve it further.