First log in to Advent of Code in your browser and fetch the cookie named 'session'.

Set it as en environment variable like this 'export SESSION = "VALUE"'

Then run the program using iex -S mix, and call the get method to get the answer, and the submit answer to post it to AoC website.

get(180101) |> submit

We follow the principle YYDDLL where

YY = Two last digit of the year, so for 2018 it would be 18

DD = The days number in two digits, so for 24th of december it would be 24

LL = Two digit number representing the level, meaning either 01 or 02

⭐⭐ 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

In order to test this before AoC 2022, I decided to solve for previous years

⭐⭐ 2016 - Day 1
⭐⭐ 2018 - Day 1
⭐⭐ 2018 - Day 2
⭐⭐ 2018 - Day 3
⭐❌ 2018 - Day 3