Advent of Code

My solutions for Advent of Code in Python with set up tools/utils for multiple years.

A rule for myself is I am going to use no AI besides Copilot tab completions and no hinting at what I want to solve with comments. Only after I solve it myself will I go back and see better ways of doing it with an LLM.

Progress

2025

• Day 1 ⭐️ ⭐️
• Day 2 ⭐️ ⭐️
• Day 3 ⭐️ ⭐️
• Day 4 ⭐️ ⭐️
• Day 5 ⭐️ ⭐️
• Day 6 ⭐️ ⭐️
• Day 7 ⭐️ ⭐️
• Day 8 ⭐️ ⭐️
• Day 9 ⭐️ ⭐️
• Day 10 ⭐️ ⭐️
• Day 11 ⭐️ ⭐️
• Day 12 ⭐️ ⭐️

Setup

Prerequisites

• Python 3.12+
• UV (for dependency management)

Installation

1. Clone the repository:

git clone https://github.com/ItsMacto/Advent-of-Code-2025.git
cd Advent-of-Code-2025

2. Sync dependencies with UV:

uv sync

3. (Optional) Set up automatic input downloading:

   • Get your AOC session cookie:

     1. Go to https://adventofcode.com/
     2. Log in
     3. Open browser DevTools (F12)
     4. Go to Application/Storage > Cookies
     5. Find the session cookie and copy its value

   • Create .aoc_session file in the project root:

     echo "YOUR_SESSION_COOKIE_HERE" > .aoc_session

   • Or set environment variable:

     export AOC_SESSION="YOUR_SESSION_COOKIE_HERE"

Usage

Create a new day

Create a day for the current year :

uv run main.py create 5

Create a day for a past year:

uv run main.py create 5 --year 2024

This creates a folder structure:

aoc2025/day5/
├── day5.py      (boilerplate with star1() and star2() functions)
├── input.txt    (will have your downloaded input if session cookie is set)
└── test.txt     (empty, for test data)

Run solutions

Run the current day of the current year (defaults if no arguments):

uv run main.py
# or
uv run main.py run

Run a specific day of the current year:

uv run main.py run 5

Run a day from a past year:

uv run main.py run 5 --year 2024

Project Structure

Advent-of-Code-2025/
├── main.py                 # CLI for creating and running days
├── download_input.py       # Download inputs from AoC
├── boilerplate.py          # Template for new days
├── pyproject.toml          # UV/Python configuration
├── .aoc_session            # Session cookie (git-ignored)
├── README.md
├── .gitignore
├── aoc2024/                # Previous year's solutions
└── aoc2025/                # Current year's solutions
    ├── __init__.py
    ├── utils/
    │   ├── __init__.py
    │   └── utils.py        # Helper functions (grid, input reading, etc.)
    ├── day1/
    │   ├── day1.py
    │   ├── input.txt
    │   └── test.txt
    ├── day2/
    └── ...

Utilities

The aoc2025/utils/utils.py module provides helpful functions:

Input Reading

from aoc2025.utils.utils import read_input

# Read input.txt as list of lines (default)
data = read_input()

# Read without splitting
data = read_input(split=False)

# Read the test.txt file
data = read_input(test=True)

# Read different file
data = read_input("other.txt")

Other Utils that I use throughout the challenges will be here also like grid handling, etc.

Solution Template

Each day follows this template:

from aoc2025.utils.utils import read_input


def star1() -> int:
    data = read_input()
    # Your solution for part 1
    return result


def star2() -> int:
    data = read_input()
    # Your solution for part 2
    return result


if __name__ == "__main__":
    print(f"Star 1: {star1()}")
    print(f"Star 2: {star2()}")

When you run a day's solution, you'll see output like:

🎄 Running 2025 Day 1:
  ⭐ Star 1: ####
  ⭐ Star 2: ####

Past Years

2024

• Day 1: ⭐️⭐️
• Day 2: ⭐️⭐️
• Day 3: ⭐️⭐️
• Day 4: ⭐️⭐️
• Day 5: ⭐️⭐️
• Day 6: ⭐️⭐️
• Day 7: ⭐️⭐️
• Day 8: ⭐️⭐️
• Day 9: ⭐️⭐️
• Day 10:⭐️⭐️
• Day 11:⭐️⭐️
• Day 12:⭐️
• Day 13:⭐️⭐️
• Day 14:⭐️⭐️
• Day 15:
• Day 16:
• Day 17:
• Day 18:
• Day 19:
• Day 20:
• Day 21:
• Day 22:
• Day 23:
• Day 24:
• Day 25:

2015

• Day 1: ⭐️⭐️
• Day 2: ⭐️⭐️
• Day 3: ⭐️⭐️
• Day 4:
• Day 5:
• Day 6:
• Day 7:
• Day 8:
• Day 9:
• Day 10:
• Day 11:
• Day 12:
• Day 13:
• Day 14:
• Day 15:
• Day 16:
• Day 17:
• Day 18:
• Day 19:
• Day 20:
• Day 21:
• Day 22:
• Day 23:
• Day 24:
• Day 25: