A C++ implementation of Hidden Binary Search Tree described in in this paper by Saulo Queiroz.
HBST maintains its height O(B) = O(log2n), where B is a size of each key in bits. This result requires no special order on the input - as does BST - nor self-balancing procedures, as do AVL and Red-Black.
HBST.hpp file contains an implementation itself, main.cpp contains some example code.
@misc{queiroz2017hidden,
title={The Hidden Binary Search Tree:A Balanced Rotation-Free Search Tree in the AVL RAM Model},
author={Saulo Queiroz},
year={2017}
}