Nice! I implemented a similar thing a while back: https://github.com/Ealdwulf/BBChop

I'm going to have to check out how you got linear time with Shannon entropy, because I used Renyi entropy to do that, to make the algebra easier.

It's also possible to do it over the DAG, rather than a linear history - although that makes the code a lot more complicated. Unfortunately there doesn't seem to be a linear time cumulative sum algorithm over dags, so it's super linear in some cases.