Have you heard about The Radix Trees?
It's an efficient data structure which is very useful for functional code. Want to know how it works?
The Radix Trees How IntMap Works
The Radix Tree (aka PATRICIA Trie) is an efficient data structure for key-value maps with integral keys. Radix tries come up in a wide range of applications like in-memory databases and the Linux kernel, and can be turned into a persistent data structure useful for functional code (Haskell's IntMap).
With pictures and code, I'll walk you through how the data structure works, what Haskell's implementation looks like under the hood and several ways it's useful in functional code. I'll finish with a look towards the future: a quick overview of the Adaptive Radix Tree, a recently published variation on normal Radix Trees with real potential.
While this talk will be Haskell flavored, the data structure itself and the general concepts are all language-agnostic.