Advent of Code 2025 solutions

Day	Title	C#	Java
1	Secret Entrance	⭐ ⭐	⭐ ⭐
2	Gift Shop	⭐ ⭐
3	Lobby	⭐ ⭐
4	Printing Department	⭐ ⭐
5	Cafeteria	⭐ ⭐
6	Trash Compactor	⭐ ⭐
7	Laboratories	⭐ ⭐
8	Playground	⭐ ⭐
9	Movie Theater	⭐ ⭐
10	Factory	⭐ ⭐
11	Reactor	⭐ ⭐
12	Christmas Tree Farm	⭐ ⭐

C# Usage instructions

To run this you'll need to provide your session cookie from the Advent of Code website in a file named session.cookie, which needs to be present in the same directory as the .exe produced by the build.

The .exe will download the input of the requested day if it's missing.

Java Usage instructions

Put the problem input under /Java/src/main/resources/.input and it will be picked up automatically.