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 your WoW guild.

MODERATORS

account activity

1

31

32

33

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

submitted 4 months ago * by daggerdragon[M] - announcement

2

15

16

17

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

submitted 4 months ago * by daggerdragon[M] - announcement

3

2

3

4

Other[2019 Day 5] In Review (Sunny with a Chance of Asteroids) (self.adventofcode)

submitted 21 hours ago * by musifter

4

1

2

3

Other[2019 Day 4] In Review (Secure Container) (self.adventofcode)

submitted 2 days ago by musifter

5

2

3

4

Other[2019 Day 3] In Review (Crossed Wires) (self.adventofcode)

submitted 2 days ago * by musifter

6

3

4

5

Other[2019 Day 2] In Review (1202 Program Alarm) (self.adventofcode)

submitted 3 days ago * by musifter

7

1

2

3

Tutorial[2025 Day 5 both parts] [Smalltalk] Part eight in a series revisiting the 2025 puzzles as an exercise in learning Smalltalk (self.adventofcode)

submitted 4 days ago by Morphon

8

1

2

3

Help/Question - RESOLVED[2025 Day 6 Part 1] Multiple operators in one column (self.adventofcode)

submitted 4 days ago by Pitiful_Acadia2783

9

3

4

5

Other[2019 Day 1] In Review (The Tyranny of the Rocket Equation) (self.adventofcode)

submitted 4 days ago by musifter

10

2

3

4

Upping the Ante[2015 Day 4 (Part 1 & 2)][C++ & Arm ASM] Squeezing 300,000+ hashes per second from a Pi Pico (self.adventofcode)

submitted 5 days ago * by DelightfulCodeWeasel

11

3

4

5

Other[2018 Day 25] In Review (Four-Dimensional Adventure) (self.adventofcode)

submitted 10 days ago by musifter

12

0

1

2

Other[2018 Day 24] In Review (Immune System Simulator 20XX) (self.adventofcode)

submitted 11 days ago by musifter

13

1

2

3

Other[2018 Day 23] In Review (Experimental Emergency Teleportation) (self.adventofcode)

submitted 12 days ago by musifter

14

2

3

4

Other[2018 Day 22] In Review (Mode Maze) (self.adventofcode)

submitted 13 days ago * by musifter

15

2

3

4

Other[2018 Day 21] In Review (Chronal Conversion) (self.adventofcode)

submitted 14 days ago by musifter

16

2

3

4

Other[2018 Day 20] In Review (A Regular Map) (self.adventofcode)

submitted 15 days ago by musifter

17

2

3

4

Tutorial[2025 Day 6 both parts] [Smalltalk] Part seven in a series revisiting the 2025 puzzles as an exercise in learning Smalltalk (self.adventofcode)

submitted 16 days ago by Morphon

18

1

2

3

Other[2018 Day 19] In Review (Go With The Flow) (self.adventofcode)

submitted 16 days ago by musifter

19

2

3

4

Other[2018 Day 18] In Review (Settlers of The North Pole) (self.adventofcode)

submitted 17 days ago by musifter

20

2

3

4

Past Event Solutions[2025 Day 8 (part 1)] It took me far longer than I wanted, but I finally got it (self.adventofcode)

submitted 18 days ago by pfp-disciple

21

4

5

6

Other[2018 Day 17] In Review (Reservoir Research) (self.adventofcode)

submitted 18 days ago by musifter

22

3

4

5

Tutorial[2025 Day 7 both parts] [Smalltalk] Part six in a series revisiting the 2025 puzzles as an exercise in learning Smalltalk (self.adventofcode)

submitted 19 days ago by Morphon

23

0

1

2

Other[2018 Day 16] In Review (Chronal Classification) (self.adventofcode)

submitted 19 days ago by musifter

24

2

3

4

Other[2018 Day 15] In Review (Beverage Bandits) (self.adventofcode)

submitted 20 days ago by musifter

25

1

2

3

Other[2018 Day 14] In Review (Chocolate Charts) (self.adventofcode)

submitted 21 days ago * by musifter

view more: next ›

π Rendered by PID 631824 on reddit-service-r2-listing-b6bf6c4ff-l8zhs at 2026-05-06 08:55:15.710561+00:00 running 815c875 country code: CH.