The use of unsorted vectors for sets was covered and benchmarked in a Scott Meyers [0] post from 2015. Facebook's folly library supports linear containers and m

The use of unsorted vectors for sets was covered and benchmarked in a Scott Meyers [0] post from 2015. Facebook's folly library supports linear containers and maps for these small sets (~100 elements, as a rule of thumb, but measure), and I've rolled my own for specific applications. [0] https://scottmeyers.blogspot.com/2015/09/should-you-be-using-something-instead.html https://scottmeyers.blogspot.com/2015/09/should-you-be-using...