best-of

-- This is still incomplete: 2016 and 2017 in particular need some more love.

The criteria for inclusion here are somewhat unclear.

=== 2015

Day 7: Some Assembly Required -- a fun early problem that maybe is mostly memorable to me because I did haskell nonsense

Day 13: Knights of the Dinner Table -- permutation city. I dunno?

Day 19: Medicine for Rudolph -- I dunno, maybe this one is just infamous.

=== 2016

Day 11: Radioisotope Thermoelectric Generators -- search, search, search! LB open for 2:45!

Day 23: Safe Cracking -- VM stuff, including reverse engineering. Day 12 is a prereq

=== 2017

Day 16: Permutation Promenade -- cute small problem with at least two solutions to part two: a beautiful one, and the one you'll probably implement

Day 18: Duet -- a solid VM puzzle mostly recommended for its trolling

=== 2018

Day 12: Subterranean Sustainability -- 1D cellular automata - I created some "Upping the Ante" puzzles that I really enjoyed solving: https://gist.github.com/msullivan/a477fd32c598da94fe495a884a440f59

Day 17: Reservoir Research -- I'm actually not sure if I liked this one or not, but it's iconic and very visual.

Day 20: A Regular Map -- another fun search problem, using a simple regex to generate a map

Day 22: Mode Maze -- search through a procedurally generated maze, with some twists

Day 23: Coprocessor Conflagration -- implementing a VM and reverse engineering a program

=== 2019

Day 12: The N-Body Problem -- light-medium maths with fun framing

Day 14: Space Stoichiometry -- search through a term rewriting system

Day 18: Many-Worlds Interpretation -- One of my favorite search AoC problems

Day 22: Slam Shuffle -- maths! One of the best AoC puzzles


2019, the IntCode sequence:
 - IntCode was kind of polarizing, but overall I liked it. Over several puzzles, you build a reasonably featured virtual machine, and which then gets reused for all the odd-numbered puzzles after day 9 in various ways, generally as a kind of black box input
  - Building the VM: days 2, 5, 9
  Intcode puzzles! I've listed more of these than maybe really deserve it, because Intcode is very "iconic 2019 AoC".

  * Day 7: Amplification Circuit -- cute reconfiguration of Intcode VMs... there is a truly elegant bullshit Haskell way to do this.
  * Day 11: Space Police -- an unusual extraction
  * Day 13: Care Package -- Play (probably programatically.) a breakout clone running in Intcode. YMMV.
  * Day 15: Oxygen System -- exploring a maze with an intcode robot
  * Day 21: Springdroid -- a puzzle, but not quite a programming one
  * Day 25: Cryostasis -- a text adventure game!

=== 2020

Day 14: Docking Data -- Good but not great, but I think the "upping the ante" problem is great: https://www.reddit.com/r/adventofcode/comments/kcybyr/2002_day_14_part_2_but_what_if_the_input_is_harder/

Day 19: Monster Messages -- kind of fine I guess

Day 20: Jurassic Jigsaw -- image reassembly

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infamy: elves v goblins, z3, fft, what else?