Write this accumuator in a functional style
Chris Angelico <rosuav at gmail.com> writes:
> some point it'll need to be rebalanced, which could at worst case
> be O(n).
No, you use a structure like an AVL tree or red-black tree, so it's
within a constant factor of balanced after each insertion. You rewrite
O(log n) of the nodes, and juggle around a constant number of them at
the top of the tree. The Wikipedia articles about those data structures
are pretty good. C++ std::map is also implemented that way, I think.