feat(blog): add advent of code 2024

content/blog/haskell/advent-of-code-2024-in-haskell.md

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+---
+title: Advent of code 2024 in Haskell
+description: I sharpened my Haskell skills again this year
+date: 2025-07-24
+tags:
+- Haskell
+---
+
+## Introduction
+
+I participated in [advent of code 2024](https://adventofcode.com/2024) in
+Haskell: it was a fun experience as always! Why writing about this now? Because
+I just finished the last puzzle!
+
+I did the first 12 puzzles each day last December but then life happened and I
+could no longer complete one puzzle per day. I only finished the first 19
+puzzles by Christmas then took the usual long break. I picked up this challenge
+again about a month ago while waiting at the airport and have now completed the
+last one.
+
+## Haskell for puzzles
+
+Usually this kind of article is an opportunity to explain some of the patterns I
+used and things I learned. Solving these puzzles was a lot of fun as always.
+
+The puzzles were interesting, my favorite one being day 24 in which you need to
+debug a binary adder. It is made of logic gates with a few wires that have been
+inverted and need to be fixed. It was the hardest challenge for me by far and I
+only solved it when I realized that instead of needing to simulate wire
+permutations I could try to build the adder from the pool of logic gates that
+were available. When I could not find a gate I needed, it meant I had to look
+for a wire to swap.
+
+I also thoroughly enjoyed day 21 where you need to input codes via proxy robots
+and need to compute a very convoluted shortest path algorithm where the key was
+careful usage of memoization.
+
+I will also make a special mention for day 13 where the problem can be reduced
+to a system of linear equations. I love an excuse to whip out a matrix
+triangularization to achieve this, but I doubly loved that I could use the
+Rational type to deal with exact ratio numbers computations. Haskell really
+shines in these situations!
+
+## Conclusion
+
+I recommend tackling this kind of challenge, it is good to maintain or develop
+proficiency in a programming language. I love Haskell, I wish I could use it
+daily and not just for seasonal puzzles.