https://github.com/narimiran/adventofcode2018
My Nim solutions for Advent of Code 2018
https://github.com/narimiran/adventofcode2018
advent-of-code advent-of-code-2018 nim nim-lang
Last synced: 2 months ago
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My Nim solutions for Advent of Code 2018
- Host: GitHub
- URL: https://github.com/narimiran/adventofcode2018
- Owner: narimiran
- License: mit
- Created: 2018-11-29T14:44:06.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2024-11-29T17:53:51.000Z (6 months ago)
- Last Synced: 2025-03-15T04:46:08.493Z (2 months ago)
- Topics: advent-of-code, advent-of-code-2018, nim, nim-lang
- Language: Nim
- Size: 159 KB
- Stars: 13
- Watchers: 5
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
# Advent of Code 2018
All my Advent of Code repos:
* [AoC 2015 in Nim, Python](https://github.com/narimiran/advent_of_code_2015)
* [AoC 2016 in Python, Clojure (+ visualizations)](https://github.com/narimiran/advent_of_code_2016)
* [AoC 2017 in Nim, OCaml, Python](https://github.com/narimiran/AdventOfCode2017)
* [AoC 2018 in Nim, Python, Racket](https://github.com/narimiran/AdventOfCode2018) (this repo)
* [AoC 2019 in OCaml, Python](https://github.com/narimiran/AdventOfCode2019)
* [AoC 2020 in Nim, one liner-y Python, Racket](https://github.com/narimiran/AdventOfCode2020)
* [AoC 2021 in Python, Racket](https://github.com/narimiran/AdventOfCode2021)
* [AoC 2022 in Python, Clojure](https://github.com/narimiran/AdventOfCode2022)
* [AoC 2023 in Clojure](https://github.com/narimiran/AdventOfCode2023)
* [AoC 2024 in Clojure (Clerk notebooks)](https://github.com/narimiran/aoc2024)
This year, I will do it once again in [Nim](https://nim-lang.org/),
and ~~later on maybe in some other language too~~ in October 2021 I practiced Racket by solving some of the puzzles,
and some time before that (in 2021) I also solved the first half of the puzzles using Python.
For Nim solutions, my aim was to provide clean, readable, idiomatic code.
Python solutions extensively use `lambda`, and the aim was to provide short (but still readable) solutions.
I'm a beginner in Racket, so the solutions here are part of my learning of the language, and consequently might not be idiomatic.
## Solutions
Task | Nim Solutions | Python Solutions | Racket Solutions | Comments (on Nim solutions)
--- | --- | --- | --- | ---
[Day 1: Chronal Calibration](https://adventofcode.com/2018/day/1) | [day01.nim](nim/day01.nim) | [day01.py](python/day01.py) | [day01.rkt](racket/day01.rkt) | Dogfooding by using [itertools](https://github.com/narimiran/itertools) to `cycle` through the input. Using `IntSet` for fast lookups.
[Day 2: Inventory Management System](https://adventofcode.com/2018/day/2) | [day02.nim](nim/day02.nim) | [day02.py](python/day02.py) | [day02.rkt](racket/day02.rkt) | The original solution used `zip`, but that allocates a new sequence.
[Day 3: No Matter How You Slice It](https://adventofcode.com/2018/day/3) | [day03.nim](nim/day03.nim) | [day03.py](python/day03.py) | [day03.rkt](racket/day03.rkt) | No need for regex, `scanf` macro is great for these kinds of inputs. Using smaller integers instead of `int` gives noticeable speed boost. Using templates to keep the main part short and readable, without unnecessary repetitions.
[Day 4: Repose Record](https://adventofcode.com/2018/day/4) | [day04.nim](nim/day04.nim) | [day04.py](python/day04.py) | [day04.rkt](racket/day04.rkt) | [2018-12-04 06:00] Guard narimiran begins shift
[Day 5: Alchemical Reduction](https://adventofcode.com/2018/day/5) | [day05.nim](nim/day05.nim) | [day05.py](python/day05.py) | [day05.rkt](racket/day05.rkt) | 4x speed improvement when using the already shortened polymer (first part) for the second part.
[Day 6: Chronal Coordinates](https://adventofcode.com/2018/day/6) | [day06.nim](nim/day06.nim) | [day06.py](python/day06.py) | [day06.rkt](racket/day06.rkt) | The slowest task so far.
[Day 7: The Sum of Its Parts](https://adventofcode.com/2018/day/7) | [day07.nim](nim/day07.nim) | [day07.py](python/day07.py) | [day07.rkt](racket/day07.rkt) | Using `heapqueue` is a no-brainer here.
[Day 8: Memory Maneuver](https://adventofcode.com/2018/day/8) | [day08.nim](nim/day08.nim) | [day08.py](python/day08.py) | [day08.rkt](racket/day08.rkt) | Using recursion is a no-brainer here.
[Day 9: Marble Mania](https://adventofcode.com/2018/day/9) | [day09.nim](nim/day09.nim) | [day09.py](python/day09.py) | [day09.rkt](racket/day09.rkt) | Compile it with `--gc:regions` to get the most performance out of it.
[Day 10: The Stars Align](https://adventofcode.com/2018/day/10) | [day10.nim](nim/day10.nim) | [day10.py](python/day10.py) | [day10.rkt](racket/day10.rkt) | The first usage of Nim templates this year. Using [unpack](https://github.com/technicallyagd/unpack) for `<-` sequence unpacking.
[Day 11: Chronal Charge](https://adventofcode.com/2018/day/11) | [day11.nim](nim/day11.nim) | [day11.py](python/day11.py) | [day11.rkt](racket/day11.rkt) | Using [summed-area table](https://en.wikipedia.org/wiki/Summed-area_table) to have O(n^3) solution (naïve solution is O(n^5)). Using threads gives 2x speed boost.
[Day 12: Subterranean Sustainability](https://adventofcode.com/2018/day/12) | [day12.nim](nim/day12.nim) | [day12.py](python/day12.py) | [day12.rkt](racket/day12.rkt) | Nothing to write home about.
[Day 13: Mine Cart Madness](https://adventofcode.com/2018/day/13) | [day13.nim](nim/day13.nim) | | | Using [complex plane](https://en.wikipedia.org/wiki/Complex_plane) is the obvious choice for the tasks like this, but `complex` in Nim is limited to floats, so I decided to use plain old tuples of integers.
[Day 14: Chocolate Charts](https://adventofcode.com/2018/day/14) | [day14.nim](nim/day14.nim) | | | Using `int8` to keep the memory usage down.
[Day 15: Beverage Bandits](https://adventofcode.com/2018/day/15) | | | | Ain't nobody got time for that.
[Day 16: Chronal Classification](https://adventofcode.com/2018/day/16) | [day16.nim](nim/day16.nim) | | | Nim bitsets don't have `pop`.
[Day 17: Reservoir Research](https://adventofcode.com/2018/day/17) | [day17.nim](nim/day17.nim) | | | Recursion keeps things nice and simple. Templates help with the readability.
[Day 18: Settlers of The North Pole](https://adventofcode.com/2018/day/18) | [day18.nim](nim/day18.nim) | | | Simplified boundary conditions by creating a border around the area.
[Day 19: Go With The Flow](https://adventofcode.com/2018/day/19) | [day19.nim](nim/day19.nim) | | | Figured out the inner loop, do it "automatically".
[Day 20: A Regular Map](https://adventofcode.com/2018/day/20) | [day20.nim](nim/day20.nim) | | | The initial solution first created a maze and then DFS-ed through it. Current solution immediately calculates the distances, for 3x performance gain.
[Day 21: Chronal Conversion](https://adventofcode.com/2018/day/21) | [day21.nim](nim/day21.nim) | | | The most interesting part of the task (figuring out what the instructions really do) was done on paper. [Here](inputs/21-annotated.txt) is a part of it.
[Day 22: Chronal Conversion](https://adventofcode.com/2018/day/22) | [day22.nim](nim/day22.nim) | | | The first time in four years that I use [`A*` algorithm](https://www.redblobgames.com/pathfinding/a-star/introduction.html#astar) for some AoC task.