AoC 2025 Framework

A Go framework for solving Advent of Code 2025 puzzles.

Structure

aoc25/
├── main.go          # Main entry point
├── days/            # Day implementations
│   ├── days.go      # Day registration and management
│   └── template.go  # Template for new days
├── input/           # Input handling
│   └── input.go     # Input parsing utilities
├── new.sh           # Script to create new days
└── README.md        # This file

Usage

Creating a New Day

Use the provided script to create a new day:

./new.sh 1

This creates:

• days/1/1.go - Day implementation file
• input/1.input - Real puzzle input
• input/1_small.input - Test/small input

Running a Day

Run a specific day with real input:

go run . -d 1

Run with small/test input:

go run . -d 1 -s

Implementing a Day

1. Edit the created file days/1/1.go
2. Set the DAY constant to the day number
3. Implement the Solve function
4. The function receives:
   • *input.Input - Parsed input data
   • *slog.Logger - Logger for debugging
5. Return the puzzle answer as an integer

Input Handling

The input.Input struct provides several methods:

• AugmentedLineStream() - Stream lines with metadata
• Lines() - Get all lines as a slice
• String() - Get entire input as a string

Gold Mode

When you want to lock in a solution and create a gold version:

./new.sh -gold 1

This:

• Creates days/1/1_gold.go (copy of your solution)
• Adds //go:build ignore to days/1/1.go

Features

• Automatic day registration - Days are registered via init() functions
• Structured logging - Each day gets its own logger
• Input management - Handles both small and real inputs
• CPU profiling - Built-in profiling for performance analysis
• Clean separation - Each day in its own directory

Dependencies

• Go 1.23.0+
• github.com/dikkadev/prettyslog for pretty logging

Example Day Implementation

package day

import (
    "log/slog"
    "github.com/dikkadev/aoc25/days"
    "github.com/dikkadev/aoc25/input"
)

const DAY = 1

func init() {
    days.RegisterDay(DAY, Solve)
}

func Solve(input *input.Input, log *slog.Logger) int {
    result := 0
    for l := range input.AugmentedLineStream() {
        if len(l.T) == 0 {
            continue
        }
        // Your solution logic here
        log.Debug(l.T)
    }
    return result
}

Tips

• Use the -s flag for debugging with small inputs
• Each day gets its own logger prefixed with "D##"
• The framework automatically handles input file paths
• Use input.AugmentedLineStream() for line-by-line processing with line numbers