That's a cool project!

I feel like the presentation of Lomuto's algorithm on p.110 would be improved by moving the i++ after the swap and making the corresponding adjustments to the accesses to i outside the loop. Also mentioning that it's Lomuto's algorithm.

These comments are probably too broad in scope to be useful this late in the project, so consider them a note to myself. C as the language for presenting the algorithms has the advantage of wide availability, not sweeping performance-relevant issues like GC under the rug, and stability, but it ends up making the implementations overly monomorphic. And some data visualizations as in Sedgewick's book would also be helpful.