A new count-distinct algorithm:

We present a simple, intuitive, sampling-based space-efficient algorithm whose description and the proof are accessible to undergraduates with the knowledge of basic probability theory.

Donald Knuth likes it: https://www-cs-faculty.stanford.edu/~knuth/papers/cvm-note.pdf

Their algorithm is not only interesting, it is extremely simple.
Furthermore, it’s wonderfully suited to teaching students who are learning the basics of computer science.
I’m pretty sure that something like this will eventually become a standard textbook topic.

There is the CWEB implementation he produced: cvm-estimates.w (archive.org)

Source: https://jmason.ie/2024/05/21/165901a.html

Interesting HackerNews comments: https://news.ycombinator.com/item?id=40379175