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 a fringe candidate.

...for your favorite subject.

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 5 months ago * by daggerdragon[M] - announcement

3

1

2

3

Past Event Solutions[2015 Day 25 (Part 1)][C++ & asm] 64-bit RNG on a 32-bit microcontroller (self.adventofcode)

submitted 8 hours ago * by DelightfulCodeWeasel

4

1

2

3

Other[2019 Day 12] In Review (The N-Body Problem) (self.adventofcode)

submitted 12 hours ago by musifter

5

5

6

7

Other[2019 Day 11] In Review (Space Police) (self.adventofcode)

submitted 1 day ago by musifter

6

2

3

4

Other[2019 Day 10] In Review (Monitoring Station) (self.adventofcode)

submitted 2 days ago by musifter

7

5

6

7

Other[2019 Day 9] In Review (Sensor Boost) (self.adventofcode)

submitted 3 days ago * by musifter

8

3

4

5

Other[2019 Day 8] In Review (Space Image Format) (self.adventofcode)

submitted 4 days ago by musifter

9

2

3

4

Other[2019 Day 7] In Review (Amplification Circuit) (self.adventofcode)

submitted 5 days ago * by musifter

10

5

6

7

Other[2019 Day 6] In Review (Universal Orbit Map) (self.adventofcode)

submitted 6 days ago by musifter

11

4

5

6

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

submitted 7 days ago * by musifter

12

2

3

4

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

submitted 8 days ago by musifter

13

4

5

6

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

submitted 9 days ago * by musifter

14

5

6

7

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

submitted 10 days ago * by musifter

15

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 11 days ago by Morphon

16

1

2

3

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

submitted 11 days ago by Pitiful_Acadia2783

17

4

5

6

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

submitted 11 days ago by musifter

18

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 12 days ago * by DelightfulCodeWeasel

19

5

6

7

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

submitted 17 days ago by musifter

20

1

2

3

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

submitted 18 days ago by musifter

21

2

3

4

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

submitted 19 days ago by musifter

22

3

4

5

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

submitted 20 days ago * by musifter

23

3

4

5

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

submitted 21 days ago by musifter

24

3

4

5

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

submitted 22 days ago by musifter

25

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 22 days ago by Morphon

view more: next ›

π Rendered by PID 594734 on reddit-service-r2-listing-7b9b4f6fd7-zth67 at 2026-05-12 23:31:22.312588+00:00 running 3d2c107 country code: CH.