aoc2025

README

Advent of Code 2025

Solutions for the 2025 Advent of Code

Building

This project makes use of Go 1.25.

go test ./...

Running the Solutions

To run a solution, use the problem name followed by the path to an input file.

For example, to run problem 2a:

$ go run main.go 1 a
Answer: 1532
Took 1.5586ms

Adding New Solutions

This currently requires the environment variable AOC_SESSION_TOKEN be set with your AdventOfCode session token.

A generator program is included that makes templates for each day, automatically downloading challenge input and updating the root command to add new subcommands for each problem. Running go generate from the repo root will generate the following for each day that is currently accessible:

• challenge/day<N>/import.go: A "glue" file combining commands for both of the day's problems to simplify wiring up subcommands
• challenge/day<N>/a.go: The main problem implementation, containing a cobra command A and the implementation func a(*challenge.Input) int
• challenge/day<N>/a_test.go: A basic test template
• challenge/day<N>/b.go: The main problem implementation, containing a cobra command B and the implementation func b(*challenge.Input) int
• challenge/day<N>/b_test.go: A basic test template
• challenge/day<N>/input.txt: The challenge input

Additionally, challenge/cmd/cmd.go will be regenerated to import and add all subcommands.

This requires goimports be available on your $PATH. Additionally, you must be export your session cookie from https://adventofcode.com as AOC_SESSION_TOKEN in you environment so the generator can download challenge inputs.

Existing solutions and challenge inputs will be skipped instead of regenerated.

License

These solutions are licensed under the MIT License.

See LICENSE for details.