Day 25 [https://adventofcode.com/2019/day/25] was fairly straightforward, once again building on Ascii generation from IntCode, as in day 17 [https://work.njae.me.uk/2019/12/

This was the challenge where I over-reached myself. Day 24 [https://adventofcode.com/2019/day/24]was about implementing a cellular automaton [https://en.wikipedia.org/wiki/Cellular_automaton], much

More encapsulated Intcode machines

Abstract algebra beats coding.

Solving by inspection

More graph contraction, and back to typeclasses

There are only two hard things in computer science...

Preprocessing and branching factors.

Stumbling in the dark, then greedy compression.

Exploiting built-in functions, and some special-case optimisation.

Searching and intcode

Blackboards and binary search

Remembering things when the game engine doesn't remind you

Adventures in polymorphism

Langton's ant, and more Intcode

In which Neil gets confused by numbers.

Back to the Intcode, tweaking some low-level bits

Some gentle data reshaping

When building your own concurrent scheduling system is the easy way.

The joys of not over-thinking the problem

Monad stacks, and debugging when things go wrong

Disarmingly straightforward.

The joys of abstractions that stay unchanged when the requirements do

Starting on monads early!