Haven't written up the last few days but I thought today's Advent of Code problem was worth a few words. I might still go back and write up a few other ones, and who knows if I'll finish any more problems - Is stopped around here last year. We'll see.

I liked today's challenge because it was a nice introduction to hash tables. Specifically, to solve the problem, you implement a simple open hash table. In some cases, you could use your languages built in hash table but then you'd have to already know something about it.

Part 1 had you do some parsing and calculating a hash function.

Part 2 required building a table of 256 items where each item held an unknown list of data items. Based on your input data, you had to either add a new item, delete an ite, or update the value of an item already in the table.

Basically a hash table. Even though the question doesn't explicitly say "hash table" it does define HASH function* and calls the process you are going to perform the "Holiday ASCII String Helper Manual Arrangement Procedure, or HASHMAP for short."

Why do I like this problem. First off, it's a nice and different way to introduce hash tables in a data structure classes but more importantly I think this type of approach can be used as a unit in a boot camp type class.

I can't tell you how many boot camp developed programmers and PD trained teachers use built in hash tables with no understanding of their limitations or in some cases real power. They use them because they were taught them and they're "easy." Dictionaries in Python or Javascript become the universal hammer.

An approach like this can be built by a relative beginner in Python, Javascript or similar using the basic constructs, including built in dictionaries but then can give a platform to explore has tables more deeply. It can also be a platform to discuss variant data structures - a hash table, but you can't just use the built in Python dictionary.

So, I'd recommend checking this one out.

The problem, once again can be found here and my solution (in Clojure), here.