TODO

• Get /haskell to work

• Fix notes on solutions and how to run

• Fix top-level makefile

• 2023 08 - solution only works as input is a special case where loops. Simpler version of loop detection would work.

• 2023 12 - accidentally saw reddit comment "use dynamic programming"

Advent of Code

My solutions to advent of code. So far contains:

• Complete 2022 in Python (done in 2022 advent season)
• Ongoing 2021 in Python and Haskell (done in 2021 advent season)
• Complete 2020 in Python (done in 2020 advent season)
• Partial 2019 in Python (started in 2020 advent season)
• Partial 2018 in Haskell (started in 2018 advent season)

In addition the others folder contains a few other attempts

• 2017 in R
• 2018 in racket

Assumes ../aoc-data (which is a private repo) holds personalized input data and solutions.

Haskell code

Single executable with one module per day that provides a solver solver function. Uses tasty for unit tests which includes Golden file testing that creates and checks ../aoc-data/good files

implicit-hie used for hie.

stack run 2015 1
stack test --test-arguments=--pattern=2018
stack test --test-arguments=--pattern=fast

Python code

Assumes Python 3.10 available. Uses poetry dependency manager (to align with repl.it)

pipx install poetry

Use poetry's virtual environment and install packages

poetry shell
poetry install

Comments

TODO

• Haskell 2018 - fill in missing
• Haskell 2018 - linting and warnings
• Python 2020 - Speed up slow solutions
• Python 2020 - Avoid duplication in Day 17
• R etc (add from aoc folder)

To improve

• 2015-04 (17s) - MD5s - find a non-naive solution that is faster
• 2015-06 (18s) - Array updates - faster

Try 2021-03 in numpy

Can we make solvers have type: (Show a, Show b) => Text -> (a, b) without having string output printed within quotes

Hints used + 2015/9 - ran web code to spot my error (missing a city) + 2018/19 googled a hint before disassembling

• 2021

• 2020 my first time completing. No major problems.

  • Done without hints except looking up the Chinese Remainder Theorem (Day 13),
  • Day 20 was the most work - lot of fiddly processing to fit the images together, but the sea monster is a nice pay off
  • Briefly stuck finding a fast method for day 23 (crab cups), saw on reddit the hint to use another data structure
  • Lots of Life

• 2019

  • Stuck on day 12 (fast method for simulating four body problem)
  • Day 13 (IntCode pong game) was fun

• 2018

  • Going back to these in Haskell in 2020/21 after doing 2019/20 in Python - clear that Python is a better fit for smaller programs were iterative improvement works, Haskell takes more effort to do easy things
  • Day 17 (water pouring) not finished in 2018, solved in 2020 after briefly looking at reddit discussion and seeing I had the wrong definition of the extent of the map for counting the final score.

Problem descriptions

TODO - Check haskell files which are not included in stack test --test-arguments=--pattern=fast

Time = Python execution time in Lines = number of python lines in solution (using pygount) Trick: 0 = just implement the instructions, 1 = needs some thought, 2 = depends on insight Done: Languages implements (p=python, j=julia, h=haskell)

| Area Description Data structures Time Lines Trick Done

2021-01 Sonar Sequence differences and averaging List 60 11 0 hjp 2021-02 Submarine Command parsing List 70 32 0 hjp 2021-03 Binary Most common bit n in a set of numbers List, Binary strings 80 50 1 hjp 2021-04 Bingo First and last bingo card to win Array (5x5) 140 64 1 hjp 2021-05 Vents Coordinates covered by multiple lines Dict (counts of coordinates) 230 55 1 hjp 2021-06 Lanternfish Number of fish with iteration rules List 60 17 2 hjp 2021-07 Crabs Minimize cost to align crabs Binary search 70 31 1 hjp 2021-08 7 segment Logical matching Dict, Set 68 69 1 p 2021-09 Smoke Minima and basins Array (2d) 87 69 1 p 2021-10 Syntax Bracket matching Stack 61 50 1 p 2021-11 Octopus flash Life-like Grid with overloads Array (10x10) 304 59 1 p 2021-12 Caves Path counting Dict (links between rooms) 994 87 1 p 2021-13 Origami Grid folding List, set 69 66 1 p 2021-14 Polymerization Apply reaction rules to chain Dict (counts) 64 60 2 p

2022-01 Calories Add groups of numbers List 2022-02 RPS Rock, paper, scissors 2022-03 2022-15 Beacons TODO B 2022-16 Valves Graph walk - TODO B: double walker 2022-17 Pyroclastic Tetris - TODO B: very long time 2022-18 Boiling 3-d flood fill Set 2022-19 2022-20 Groves Circular list mixing List 2022-21 Math Tree of math operations 2022-22 Map Movement on cube surface 2022-23 Diffusion Life-like Set