Advent of code 2021

My run for 2021's Advent of code :)

I'll be doing this first run in Python. Maybe I'll try Go or Kotlin later to learn the languages.
Tests are only being added when necessary to debug faulty solutions.

Instructions

Inputs should be saved to inputs/input_0X.txt. One file per puzzle.
Installing depedencies: pip install -r requirements.txt.
Executing the code: python -m advent.puzzle_01.