Advent of Code 2020

All my Advent of Code repos:

• AoC 2015 in Nim, Python
• AoC 2016 in Python, Clojure (+ visualizations)
• AoC 2017 in Nim, OCaml, Python
• AoC 2018 in Nim, Python, Racket
• AoC 2019 in OCaml, Python
• AoC 2020 in Nim, one liner-y Python, Racket (this repo)
• AoC 2021 in Python, Racket
• AoC 2022 in Python, Clojure
• AoC 2023 in Clojure
• AoC 2024 in Clojure (Clerk notebooks)

 

Solutions

Task	Nim	Python	Racket	Comments (for Nim solutions)
Day 1: Report Repair	day01.nim	day01.py	day01.rkt	Small check elif s[i] + s[j] < 2020: makes the whole program ~4x faster.
Day 2: Password Philosophy	day02.nim	day02.py	day02.rkt	scanf useful as always.
Day 3: Toboggan Trajectory	day03.nim	day03.py	day03.rkt	Keeping it below 20 lines :)
Day 4: Passport Processing	day04.nim	day04.py	day04.rkt	Had a nasty early morning bug with if not v.len == 9. Argh.
Day 5: Binary Boarding	day05.nim	day05.py	day05.rkt	Traversing a sorted list is more efficient than looking for every number in unsorted one.
Day 6: Custom Customs	day06.nim	day06.py	day06.rkt	Classic AoC-use-sets tasks.
Day 7: Handy Haversacks	day07.nim	day07.py	day07.rkt	Babushka bag = Bagushka.
Day 8: Handheld Halting	day08.nim	day08.py	day08.rkt	Faster than it looks.
Day 9: Encoding Error	day09.nim	day09.py	day09.rkt	Sliding slice sum.
Day 10: Adapter Array	day10.nim	day10.py	day10.rkt	CountTable to the rescue.
Day 11: Seating System	day11.nim			The ugliest and the slowest solution so far.
Day 12: Rain Risk	day12.nim	day12.py	day12.rkt	Using complex numbers is soooo last Tuesday. No Complex this time.
Day 13: Shuttle Search	day13.nim	day13.py	day13.rkt	Yeah yeah, CRT, but it took me way too long to implement it correctly.
Day 14: Docking Data	day14.nim			Good luck trying to understand what's going on.
Day 15: Rambunctious Recitation	day15.nim			Boring.
Day 16: Ticket Translation	day16.nim			Naming is hard.
Day 17: Conway Cubes	day17.nim			Nobody notices your 9 nested for-loops if you hide them in a template.
Day 18: Operation Order	day18.nim			Template and streams make this one really elegant.
Day 19: Monster Messages	day19.nim			My first experience with npeg.
Day 20: Jurassic Jigsaw
Day 21: Allergen Assessment	day21.nim			Day 16, part 2 vibes.
Day 22: Crab Combat	day22.nim			Deque Deck for Crab Combat.
Day 23: Crab Cups	day23.nim			No Linked List for Crab Cups: 10x faster and lighter (less memory usage).
Day 24: Lobby Layout	day24.nim			Read redblobgames if you haven't already.
Day 25: Combo Breaker	day25.nim

Run times

• Nim version 1.5.1 (devel)
• compiled with -d:danger --gc:arc
• CPU: AMD Ryzen 3700x @ 3.6 GHz (Linux 5.4)

The reported results are the average of 20 runs.

01     0.72 ms
02     0.82 ms
03     0.63 ms
04     1.23 ms
05     0.80 ms
06     0.96 ms
07     1.89 ms
08     1.06 ms
09     1.01 ms
10     0.72 ms
11    26.66 ms
12     0.93 ms
13     0.63 ms
14    11.57 ms
15   583.13 ms
16     4.62 ms
17    64.36 ms
18     1.48 ms
19    17.52 ms
20    12.16 ms
21     1.86 ms
22     1.06 ms
23   208.55 ms
24    16.32 ms
25     5.42 ms
--------------
        966 ms