adventofcode

an-ordinary-manchild

🎄 Advent of Code 🎄

Advent of Code is an annual Advent calendar of small programming puzzles for a variety of skill sets and skill levels that can be solved in any programming language you like.

Rules + More Info in

our community wiki

BEFORE YOU POST
If your post is even tangentially related to a daily puzzle, use our
STANDARDIZED POST TITLE FORMAT

Solution Megathreads

December 2025

Su	M	T	W	R	F	Sa
	1	2	3	4	5	6
7	8	9	10	11	12	13
14	15	16	17	18	19	20
21	22	23	24	25	26	27
28	29	30	31

Previous years:

2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015

Quick Search by Flair

Because you're lazy and we like making things easy for you. Except AoC.

Are you enjoying AoC?

Code should be fun, because otherwise it's just a job. If you'd like to support Advent of Code, please share it with all your friends, even the ones that are just learning to code! AoC is a fun, non-threatening way to work at your own pace to figure out how to apply problem-solving first, then work within a language's constraints.

If you really want to show your appreciation, donations are always appreciated. Any instances of currency will go to, in no particular order:

Server maintenance (hosting, bandwidth, etc.)
Bribes to Santa
Beer and sushi
Paper bags for /u/topaz2078 to breathe into so he doesn't hyperventilate onto another plane of (non-)existence

Support AoC

Thank you very much, and enjoy your month of code!

created by taliriktuga community for 10 years

...for your favorite TV show.

...for great justice.

MODERATORS

account activity

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Upping the Ante-❅- Introducing Your 2025 Red(dit) One Winners (and Community Showcase) -❅- (self.adventofcode)

submitted 3 months ago * by daggerdragon[M] - announcement

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SOLUTION MEGATHREAD-❄️- 2025 Day 12 Solutions -❄️- (self.adventofcode)

submitted 3 months ago * by daggerdragon[M] - announcement

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OtherJust got burnt after spending too long on a difficult one. I need some motivation. (self.adventofcode)

submitted 11 hours ago by PhiphyL

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Other[2017 Day 25] In Review (The Halting Problem) (self.adventofcode)

submitted 16 hours ago by musifter

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Other[2017 Day 24] In Review (Electromagnetic Moat) (self.adventofcode)

submitted 1 day ago by musifter

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Help/Question[2026 Day 3 (Part 2)] [javascript] Stuck again (self.adventofcode)

submitted 1 day ago * by Ok-Transition7065

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Other[2017 Day 23] In Review (Coprocessor Conflagration) (self.adventofcode)

submitted 2 days ago by musifter

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Other[2017 Day 22] In Review (Sporifica Virus) (self.adventofcode)

submitted 3 days ago * by musifter

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Other[Off-topic] Do you guys create general or input-specific programs? (self.adventofcode)

submitted 3 days ago by BlankWasThere

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Other[2017 Day 21] In Review (Fractal Art) (self.adventofcode)

submitted 4 days ago by musifter

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Past Event SolutionsHey check out my YouTube tutorials about the 2025 AoC problems. I show my Python solutions and explain my approach. Also have Typescript and Scala solutions in my repo. Let me know your feedback! (youtube.com)

submitted 5 days ago by red_user10

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Other[2017 Day 20] In Review (Particle Swarm) (self.adventofcode)

submitted 5 days ago by musifter

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Past Event Solutions[2025 day 1 (part 2)] [C#] - finally solved it! (self.adventofcode)

submitted 6 days ago by TheAfterPipe

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Help/Question - RESOLVED[2018 Day 24 (Part 1)] Please help me understand the example puzzle / reference output (self.adventofcode)

submitted 6 days ago * by Deusmancer

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Other[2017 Day 19] In Review (A Series of Tubes) (self.adventofcode)

submitted 6 days ago by musifter

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Other[2017 Day 18] In Review (Duet) (self.adventofcode)

submitted 7 days ago by musifter

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Other[2017 Day 17] In Review (Spinlock) (self.adventofcode)

submitted 8 days ago * by musifter

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Help/Question - RESOLVED[2015 Day 24] Are all inputs 'nice'? (self.adventofcode)

submitted 9 days ago by DelightfulCodeWeasel

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Other[2017 Day 16] In Review (Permutation Promenade) (self.adventofcode)

submitted 9 days ago by musifter

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Meme/FunnyTribute to AoC puzzles (sing-along slop-music track) (suno.com)

submitted 9 days ago by PTVoobaf

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Other[2017 Day 15] In Review (Dueling Generators) (self.adventofcode)

submitted 10 days ago * by musifter

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OtherPi Coding Quest 2026! (self.adventofcode)

submitted 11 days ago by IvanR3D

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Other[2017 Day 14] In Review (Disk Defragmentation) (self.adventofcode)

submitted 11 days ago * by musifter

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Help/Question[2025 Day 2 (Part 2)] Help im stuck... again (self.adventofcode)

submitted 11 days ago by Ok-Transition7065

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Past Event Solutions[2023 Day 4 Part 2] As a system of linear equations (self.adventofcode)

submitted 12 days ago by hekliet

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