Advent of Code Solutions

Multi-year Advent of Code solutions exploring different programming languages and paradigms.

Project Structure

aoc/
├── 2025/          # Zig solutions
├── 2024/          # C++ solutions
├── 2023/          # Rust solutions
├── 2022/          # OCaml solutions
├── common/        # Shared utilities per language
│   ├── rust/      # Rust common library
│   ├── ocaml/     # OCaml common library
│   └── cpp/       # C++ common library
├── justfile       # Root task runner
└── scripts/       # Meta-project utilities

Quick Start

# Run a specific day
just run <year> <day>

# Test with sample input
just test <year> <day>

# Create a new day solution
just new <year> <day>

# Show all available commands
just --list

Languages by Year

Year	Language	Build Tool	Paradigm
2025	Zig 0.13	zig	Systems, imperative
2024	C++17	g++	Imperative, OOP
2023	Rust	Cargo	Systems, functional-ish
2022	OCaml	Dune/opam	Functional

Each year explores different strengths:

• Zig: Simplicity, explicit control, fast compile times, comptime
• C++: Performance, low-level control, STL algorithms
• Rust: Memory safety, zero-cost abstractions, strong type system
• OCaml: Pattern matching, immutability, algebraic types

Year-Specific Documentation

Each year has its own README with detailed setup and workflow:

• 2025 README - Zig setup and memory management
• 2024 README - C++ setup and commands
• 2023 README - Rust workspace structure
• 2022 README - OCaml/Dune configuration

Common Libraries

Shared utilities to reduce boilerplate across solutions:

• 2023/common - Rust: CLI parsing, input handling, colored output
• 2022/common - OCaml: File I/O helpers
• 2024/common - C++: Common utilities

Project Commands

Running Solutions

# From project root
just run 2023 8        # Run 2023 day 8 with input
just test 2024 1       # Test 2024 day 1 with sample

# From year directory (e.g., cd 2023)
just run 8             # Run day 8
just test 8 2          # Test day 8 part 2

Creating New Solutions

# From root
just new 2024 15       # Create day 15 for 2024

# From year directory
just new 15            # Create day 15 for current year

The new command creates:

• Day directory with template code
• Empty input and sample files
• Language-specific build configuration

Building and Testing

# Build specific day
just 2023/build 8

# Run all Rust tests (2023 workspace)
just test-all

# Run clippy on all Rust code
just check

# Clean build artifacts
just clean 2023        # Clean specific year

Utilities

# Show progress for a year
just progress 2023

# Fetch puzzle input (requires AOC session token)
just fetch 2024 10

# Benchmark a solution
just bench 2023 8

# Generate statistics
just stats

Development Workflow

1. Start new day: just new 2024 5
2. Copy input: Add puzzle input to 2024/5/input
3. Add sample: Add example from problem to 2024/5/sample_1
4. Implement: Edit solution file (main.cpp, main.rs, or main.ml)
5. Test: just test 2024 5 to verify with sample
6. Run: just run 2024 5 to solve with actual input
7. Iterate: Refine for part 2

Starting a New Year

See NEW_YEAR.md for a guide on setting up a new year (2025, etc.).

Meta-Project Tools

• Progress Tracking: Visual dashboard of completion status
• Input Fetching: Automatic puzzle input download
• Benchmarking: Performance comparison across solutions
• Stats Generation: Lines of code, completion rates, language metrics

Repository Structure

• Cargo.toml - Rust workspace configuration (2023 + common)
• dune-workspace - OCaml workspace configuration (2022)
• justfile - Root task runner, delegates to year-specific justfiles
• .editorconfig - Consistent formatting across editors
• rust-toolchain.toml - Rust version specification

Requirements

All Years

• Just - Task runner
• Git - Version control

2025 (Zig)

• Zig ≥ 0.13.0
• Install: just 2025/install-toolchain or download from ziglang.org

2024 (C++)

• g++ with C++17 support
• Install: just 2024/install-toolchain or brew install gcc (macOS)

2023 (Rust)

• Rust toolchain (specified in rust-toolchain.toml)
• cargo-nextest: cargo install cargo-nextest
• Install: just 2023/install-toolchain

2022 (OCaml)

• OCaml ≥ 5.3.0
• opam - Package manager
• Dune ≥ 3.17.0
• Install: just 2022/install-toolchain

Configuration

AOC Session Token

For automatic input fetching:

# Store your session cookie
echo "your-session-token" > ~/.config/aoc-session
chmod 600 ~/.config/aoc-session

Get your session token from browser dev tools when logged into adventofcode.com.

Tips

• Language Choice: Pick the language that best fits the problem type
  • Parsing heavy? OCaml's pattern matching shines
  • Performance critical? C++ or Rust
  • Complex state? Rust's type system helps
• Common Libraries: Extract repeated patterns into common libraries
• Templates: Year-specific templates encode common solution structure
• Sample Tests: Always test with sample input before running on actual input
• Incremental: Start simple, refactor as patterns emerge

Contributing

This is a personal learning project, but feel free to:

• Open issues for bugs or suggestions
• Share interesting alternative solutions
• Suggest additional meta-project tooling

License

MIT - See LICENSE.md