Advent Of Code

These are all my solutions to Advent of Code. I solve in Python for speed (although I clean up the code a bit afterwards) and starting in 2021 I decided to see how far I could get with SQLite and Google Sheets for fun. The former two are in this repo, the Google Sheets solutions are in a Google Drive folder.

If you want to join my private leaderboard, use the join code: 218680-10f0ed92

Setup

1. Clone this repo.
2. From the root of the repo use python -m venv venv to create a virtualenv.
3. Use source venv/bin/activate to active the virtualenv.
4. Run pip install -r requirements.txt to install dependencies.
5. Create a .env file AOC_SESSION_COOKIE=<session cookie> in it. To find your session cookie, log into AoC and in your browser's devtools, find the value of the cookie named session.

Download input files

To download the input for a given day, run python download_input.py <year> <day>. The output will be put in a file named <year>/day<day>.txt.

Using the Python template

The template is broken up into four sections. At the top are a bunch of imports that are commonly used so you don't have to remember to go import them. The get_input function's job is to read the input from a text file and parse it. The part1 and part2 functions are fed the input (whatever get_input returns) and are expected to return the answer to that part. Lastly is the section the parses command-line options and calls the other three functions.

Each day, copy template.py to day<day>.py. By default get_input uses the filename of the script (with .py changed to .txt) to find the input file. The first part you should edit is is the last line of get_input. The first four lines of that function read the file. The last line by default just splits it into lines. But it usually makes sense to do something to parse each line, like into a tuple of of integers if it was a comma separated list of numbers, or to parse values out of a regex, or something else.

Next implement the part 1 function. Big caveat here: don't mutate the input that is passed to it! That same input is passed to part2 and if you change the input, the part2 output will be wrong. Do a copy or a deep copy if you have to. If there is some computation shared between part1 and part2 I recommend adding extra common helper functions.

Running the Python code

For any day, run python day<day>.py. With no other arguments it will load the default input and run parts 1 and 2. To run only one of the parts, pass --part1 or --part2. --part2 is especially helpful on days where part 1 is slow and you want to get the answer to part 2 without having to re-run part 1, or if you accidentally mutated the input in part 1 and want to run part 2 with the original input without having to fix part 1 right away. If you want to try the code on some other input, you can put that other input in a separate file and pass its name on the command line (but I usually just overwrite the real input file and then revert it). Lastly, if you use --clip it will copy the last non-null solution to the clipboard so you can paste it directly into the AoC answer box.

Running the SQLite solutions

Run sqlite3 < day<day>.sql. All the SQLite solutions just read the default day<day>.txt input files.

Examples of some techniques

• ASM
  • 2015/day23
  • 2016/day12
  • 2016/day23
  • 2016/day25
  • 2017/day18 (mutual recursion)
  • 2017/day23
  • 2018/day16
  • 2018/day19
  • 2018/day21
  • 2019/day2 (intcode)
  • 2019/day5 (intcode)
  • 2019/day7 (intcode)
  • 2019/day9 (intcode)
• A*
  • 2015/day19
  • 2015/day22
  • 2016/day13
  • 2016/day17
  • 2016/day22
  • 2016/day24
  • 2018/day22
• BFS
  • 2016/day24
• Union/Find
  • 2017/day14
• Permutations
  • 2015/day9
  • 2015/day13
  • 2016/day24
• Count Bits
  • 2017/day14
• Vector
  • 2017/day20
• Maze
  • 2016/day24
• Skipping Iteration
  • 2018/day12
  • 2018/day18
• Graphical
  • 2018/day13
  • 2018/day15
  • 2018/day17
  • 2018/day18
• Game of Life
  • 2018/day18