A look back on my experience of Advent of Code 2023.

Pseudo-random brute force is good enough. And perhaps the longest import list of the event!

Linear algebra solvers, and using Rational numbers.

An NP-hard problem somewhat tamed by preprocessing and a small instance of the problem.

Coordinate geometry and graph processing. What's not to love?

Solving a discrete maths puzzle rather than a programming puzzle.

RWS monads, and reverse-engineering the puzzle input.

Using the type system keeps me on track, and lenses and monoids keep things simple.

A day of two halves: parsing and calculation.

A lesson on not overthinking things, except when I used phantom types.

First use of pattern synonyms.

The parsing got to me eventually.

Finding loops, and off-by-many errors.

Lots of use of standard list functions.

A good choice for part 1 pays dividends for part 2.

The day to practise search.

The return of the Difference Engine