Always pleasure to see short implementations, but I’d still take HNSW over such approach. Its core implementation can also be quite compact. In our case with USearch [1] its about 2k LOC, even with a custom implementation of priority queues and custom numeric types like uint40_t for indexes beyond 4B points.

Obviously, together with bindings for Rust, Python, JavaScript, Java, Objective-C, Swift, and Wolfram it gets slightly larger, but on the bright side, you can pass JIT-compiled functions and store/search elements of different dimensionality, which allows much broader applicability [2].

[1]: https://github.com/unum-cloud/usearch [2]: https://ashvardanian.com/posts/abusing-vector-search