Open addressing or ‘open bucket’ hash tables always seem to be a second consideration in textbooks or blogs. I find them generally faster, and more memory efficient, and easier to implement. - HN / wikipedia

• Optimizing Open Addressing / HN

• Inside boost::unordered_flat_map - boost::unordered_flat_map is the fastest open-addressing hash map implementation in this field for C++… it outperforms absl::flat_hash_map
• Hash Tables: Open Addressing