Advent of Code 2025

Open in Code Editor Copy Instructions Submit Solution

The "Advent of Code" is a series of yearly coding tasks (previous years had 25, this year 12 - each with 2 parts) released on the 1st December each year

This was the first ever monthly challenge 1 year ago at the end of 2024 - we got a few good solutions from users

With significantly more active users of the site now than back then, let's see how many of the challenges we can complete as a community

Some will most likely be too difficult/be more practical with more advanced data structures - but many should still be possible. As a minimum, let's see if we can get working pseudocode solutions for at least 6 of the 12 part 1 challenges and 3-4 or more of the part 2 challenges

The list of challenges are below:

Advent of Code challenges

If you have a working solution, please name it sensibly like - "Advent of Code 2025 | Day 1 - Part 1 | [ChallengeName]"

Grid Traversal

[Guest]

Advent of Code 2025 | Day 1 - Part 1 | Secret Entrance

liang.ren@dulwich.org

Advent of Code 2025 | Day 1 - Part 2 | Secret Entrance

liang.ren@dulwich.org

Submission Instructions

Create your program on the editor page, then click the upload button at the bottom of the code editor as shown below

Once you are confident your program is working well without obvious bugs, then give it a relevant name, choose the current monthly challenge from the dropdown box, choose some program categories if you want and submit it :)

Note: your submitted programs will be in blue and you can overwrite them by opening them, clicking the upload button again and selecting "overwrite"