https://github.com/martinus/unordered_dense https://github.com/martinus/unordered_dense Check this one out, it's a successor to this idea. Boost also introduce

https://github.com/martinus/unordered_dense https://github.com/martinus/unordered_dense Check this one out, it's a successor to this idea. Boost also introduced a very performant flat_hash_map in 1.81