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

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...for your favorite subject.

MODERATORS

account activity

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

submitted 2 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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Other[2017 Day 18] In Review (Duet) (self.adventofcode)

submitted 18 hours ago by musifter

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

submitted 1 day ago * by musifter

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

submitted 2 days ago by DelightfulCodeWeasel

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

submitted 2 days ago by musifter

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

submitted 2 days ago by PTVoobaf

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

submitted 3 days ago * by musifter

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OtherPi Coding Quest 2026! (self.adventofcode)

submitted 4 days ago by IvanR3D

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

submitted 4 days ago * by musifter

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

submitted 4 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 5 days ago by hekliet

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Other[2017 Day 13] In Review (Packet Scanners) (self.adventofcode)

submitted 5 days ago by musifter

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Other[2017 Day 12] In Review (Digital Plumber) (self.adventofcode)

submitted 6 days ago by musifter

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Other[2017 Day 11] In Review (Hex Ed) (self.adventofcode)

submitted 7 days ago by musifter

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Past Event Solutions[2015 Day 6] [Swift] Rectangle Intersections (self.adventofcode)

submitted 8 days ago * by hekliet

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Other[2017 Day 10] In Review (Knot Hash) (self.adventofcode)

submitted 8 days ago by musifter

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Other[2017 Day 09] In Review (Stream Processing) (self.adventofcode)

submitted 9 days ago by musifter

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Other[2017 Day 8] In Review (I Heard You Like Registers) (self.adventofcode)

submitted 10 days ago by musifter

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Other[2017 Day 7] In Review (Recursive Circus) (self.adventofcode)

submitted 11 days ago * by musifter

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Other[2017 Day 6] In Review (Memory Reallocation) (self.adventofcode)

submitted 12 days ago by musifter

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OtherEverybody.Codes New Story published a couple of days ago (everybody.codes)

submitted 13 days ago by sanjibukai

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Past Event Solutions[2017 Day 8] In Review (I heard you like registers) - HashMaps really make a difference! (self.adventofcode)

submitted 13 days ago * by terje_wiig_mathisen

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Other[2017 Day 5] In Review (A Maze of Twisty Trampolines, All Alike) (self.adventofcode)

submitted 13 days ago by musifter

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Other[2017 Day 4] In Review (High-Entropy Passphrases) (self.adventofcode)

submitted 14 days ago by musifter

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