Advent of Code

Complete 2023 to 2019 and 2016 to 2015 entries for the annual Advent of Code challenge, written in performant Rust.

Features

• Each solution is blazing fast, using the most efficient algorithms to the best of my knowledge.
• Clean, elegant and idiomatic code.
• Consistently formatted with rustfmt and linted by clippy.
• Thoroughly commented with rustdoc generated documentation online.
• Test coverage with continuous integration provided by GitHub Actions.
• Self contained depending only on the stable std Rust library. No use of unsafe features.

Quickstart

Show details

Input

Place input files in input/yearYYYY/dayDD.txt including leading zeroes. For example:

• input/year2015/day23.txt
• input/year2023/day02.txt

Run

• Everything cargo run
• Specific year cargo run year2023
• Specific day cargo run year2023::day01
• Release profile (faster) cargo run --release
• Optimized for current CPU architecture (fastest) RUSTFLAGS="-C target-cpu=native" cargo run --release

Test

• Everything cargo test
• Specific year cargo test year2023
• Specific day cargo test year2023::day01
• Show STDOUT for debugging cargo test -- --nocapture

Benchmark

• Everything cargo bench
• Specific year cargo bench year2023
• Specific day cargo bench year2023::day01

Document

• Build docs including private items cargo doc --document-private-items
• Build doc then open HTML landing page cargo doc --document-private-items --open

Miscellaneous

• Code quality lints cargo clippy
• Consistent code formatting cargo fmt

Performance

Benchmarks are measured using the built-in cargo bench tool run on an Apple M2 Max. All 175 solutions from 2023 to 2019 and also 2016 to 2015 complete sequentially in 1.1 seconds. Interestingly 90% of the total time is spent on just 5 solutions. Performance is reasonable even on older hardware, for example a 2011 MacBook Pro with an Intel i7-2720QM processor takes 4.1 seconds to run the same 175 solutions.

Year	Benchmark (ms)
2023	7
2022	10
2021	10
2020	286
2019	22
2017	in progress
2016	663
2015	87

2023

Day	Problem	Solution	Benchmark (μs)
1	Trebuchet?!	Source	35
2	Cube Conundrum	Source	10
3	Gear Ratios	Source	55
4	Scratchcards	Source	18
5	If You Give A Seed A Fertilizer	Source	19
6	Wait For It	Source	1
7	Camel Cards	Source	97
8	Haunted Wasteland	Source	34
9	Mirage Maintenance	Source	19
10	Pipe Maze	Source	60
11	Cosmic Expansion	Source	12
12	Hot Springs	Source	514
13	Point of Incidence	Source	64
14	Parabolic Reflector Dish	Source	661
15	Lens Library	Source	83
16	The Floor Will Be Lava	Source	831
17	Clumsy Crucible	Source	2463
18	Lavaduct Lagoon	Source	19
19	Aplenty	Source	100
20	Pulse Propagation	Source	6
21	Step Counter	Source	180
22	Sand Slabs	Source	41
23	A Long Walk	Source	632
24	Never Tell Me The Odds	Source	96
25	Snowverload	Source	157

2022

Day	Problem	Solution	Benchmark (μs)
1	Calorie Counting	Source	14
2	Rock Paper Scissors	Source	4
3	Rucksack Reorganization	Source	15
4	Camp Cleanup	Source	7
5	Supply Stacks	Source	14
6	Tuning Trouble	Source	3
7	No Space Left On Device	Source	10
8	Treetop Tree House	Source	55
9	Rope Bridge	Source	122
10	Cathode-Ray Tube	Source	2
11	Monkey in the Middle	Source	1172
12	Hill Climbing Algorithm	Source	59
13	Distress Signal	Source	16
14	Regolith Reservoir	Source	205
15	Beacon Exclusion Zone	Source	2
16	Proboscidea Volcanium	Source	60
17	Pyroclastic Flow	Source	68
18	Boiling Boulders	Source	129
19	Not Enough Minerals	Source	71
20	Grove Positioning System	Source	5067
21	Monkey Math	Source	61
22	Monkey Map	Source	55
23	Unstable Diffusion	Source	2017
24	Blizzard Basin	Source	80
25	Full of Hot Air	Source	3

2021

Day	Problem	Solution	Benchmark (μs)
1	Sonar Sweep	Source	6
2	Dive!	Source	11
3	Binary Diagnostic	Source	20
4	Giant Squid	Source	11
5	Hydrothermal Venture	Source	179
6	Lanternfish	Source	1
7	The Treachery of Whales	Source	1
8	Seven Segment Search	Source	16
9	Smoke Basin	Source	55
10	Syntax Scoring	Source	33
11	Dumbo Octopus	Source	58
12	Passage Pathing	Source	27
13	Transparent Origami	Source	32
14	Extended Polymerization	Source	12
15	Chiton	Source	2567
16	Packet Decoder	Source	5
17	Trick Shot	Source	7
18	Snailfish	Source	461
19	Beacon Scanner	Source	554
20	Trench Map	Source	2075
21	Dirac Dice	Source	282
22	Reactor Reboot	Source	398
23	Amphipod	Source	1717
24	Arithmetic Logic Unit	Source	4
25	Sea Cucumber	Source	621

2020

Day	Problem	Solution	Benchmark (μs)
1	Report Repair	Source	11
2	Password Philosophy	Source	35
3	Toboggan Trajectory	Source	11
4	Passport Processing	Source	43
5	Binary Boarding	Source	12
6	Custom Customs	Source	35
7	Handy Haversacks	Source	55
8	Handheld Halting	Source	7
9	Encoding Error	Source	9
10	Adapter Array	Source	1
11	Seating System	Source	4847
12	Rain Risk	Source	11
13	Shuttle Search	Source	1
14	Docking Data	Source	79
15	Rambunctious Recitation	Source	160000
16	Ticket Translation	Source	102
17	Conway Cubes	Source	414
18	Operation Order	Source	26
19	Monster Messages	Source	384
20	Jurassic Jigsaw	Source	38
21	Allergen Assessment	Source	51
22	Crab Combat	Source	6105
23	Crab Cups	Source	110000
24	Lobby Layout	Source	4346
25	Combo Breaker	Source	24

2019

Day	Problem	Solution	Benchmark (μs)
1	The Tyranny of the Rocket Equation	Source	1
2	1202 Program Alarm	Source	1
3	Crossed Wires	Source	19
4	Secure Container	Source	7
5	Sunny with a Chance of Asteroids	Source	3
6	Universal Orbit Map	Source	28
7	Amplification Circuit	Source	275
8	Space Image Format	Source	5
9	Sensor Boost	Source	1356
10	Monitoring Station	Source	1001
11	Space Police	Source	470
12	The N-Body Problem	Source	1024
13	Care Package	Source	3492
14	Space Stoichiometry	Source	17
15	Oxygen System	Source	442
16	Flawed Frequency Transmission	Source	4124
17	Set and Forget	Source	425
18	Many-Worlds Interpretation	Source	1077
19	Tractor Beam	Source	817
20	Donut Maze	Source	191
21	Springdroid Adventure	Source	2265
22	Slam Shuffle	Source	11
23	Category Six	Source	871
24	Planet of Discord	Source	139
25	Cryostasis	Source	2721

2017

Day	Problem	Solution	Benchmark (μs)
1	Inverse Captcha	Source	1
2	Corruption Checksum	Source	3
3	Spiral Memory	Source	2
4	High-Entropy Passphrases	Source	94
5	A Maze of Twisty Trampolines, All Alike	Source	48000
6	Memory Reallocation	Source	81
7	Recursive Circus	Source	85
8	I Heard You Like Registers	Source	46
9	Stream Processing	Source	13
10	Knot Hash	Source	61
11	Hex Ed	Source	20
12	Digital Plumber	Source	59
13	Packet Scanners	Source	2
14	Disk Defragmentation	Source	422

2016

Day	Problem	Solution	Benchmark (μs)
1	No Time for a Taxicab	Source	3
2	Bathroom Security	Source	9
3	Squares With Three Sides	Source	26
4	Security Through Obscurity	Source	75
5	How About a Nice Game of Chess?	Source	212000
6	Signals and Noise	Source	5
7	Internet Protocol Version 7	Source	354
8	Two-Factor Authentication	Source	10
9	Explosives in Cyberspace	Source	6
10	Balance Bots	Source	17
11	Radioisotope Thermoelectric Generators	Source	785
12	Leonardo's Monorail	Source	1
13	A Maze of Twisty Little Cubicles	Source	4
14	One-Time Pad	Source	434000
15	Timing is Everything	Source	1
16	Dragon Checksum	Source	1
17	Two Steps Forward	Source	14254
18	Like a Rogue	Source	743
19	An Elephant Named Joseph	Source	1
20	Firewall Rules	Source	23
21	Scrambled Letters and Hash	Source	10
22	Grid Computing	Source	31
23	Safe Cracking	Source	1
24	Air Duct Spelunking	Source	335
25	Clock Signal	Source	1

2015

Day	Problem	Solution	Benchmark (μs)
1	Not Quite Lisp	Source	2
2	I Was Told There Would Be No Math	Source	8
3	Perfectly Spherical Houses in a Vacuum	Source	100
4	The Ideal Stocking Stuffer	Source	76000
5	Doesn't He Have Intern-Elves For This?	Source	39
6	Probably a Fire Hazard	Source	5780
7	Some Assembly Required	Source	27
8	Matchsticks	Source	12
9	All in a Single Night	Source	35
10	Elves Look, Elves Say	Source	14
11	Corporate Policy	Source	1
12	JSAbacusFramework.io	Source	80
13	Knights of the Dinner Table	Source	39
14	Reindeer Olympics	Source	28
15	Science for Hungry People	Source	41
16	Aunt Sue	Source	21
17	No Such Thing as Too Much	Source	43
18	Like a GIF For Your Yard	Source	161
19	Medicine for Rudolph	Source	188
20	Infinite Elves and Infinite Houses	Source	1671
21	RPG Simulator 20XX	Source	3
22	Wizard Simulator 20XX	Source	257
23	Opening the Turing Lock	Source	6
24	It Hangs in the Balance	Source	360
25	Let It Snow	Source	1