advent-of-code-2023

Advent of Code 2023 solutions in Java 21

Goals

1. Solve all the tasks
   • ✅ (with help)
2. Write nice code
   • ❔ you should tell this; I have tried
3. Only use java.base
   • ✅ (in the module-info.java you can also find java.net.http, this is only used to download the inputs; nothing is used in the solutions from it)
4. Have all days as a standalone runnable Java file (So, like standing in the aoc2023 folder, you could execute the day, like: java src/main/java/io/github/zebalu/aoc2023/days/Day01.java. This also means if you want to understand how a solution works, you only need to read 1 file.)
   • ✅ Done! And none of them is longer then 300 lines. So if you need help, only 300 lines to read. (I know, for someone in Python this is half of a dissertation...)

Stretch goals

1. All the days separately should run under 1 sec (without JVM startup)
   • ✅ Done! I was close to give up, but I have managed to make it. (Again, with help.)
2. All the days together should run under 10 sec (without JVM startup)
   • ✅ Done! See above...

Where are the inputs?

Compared to previous years I have found out, the maker of AoC does not want us to share the inputs. All others are in git history, so there is no use getting rid of them, but this year I won't upload any.

But

You can set an environment variable AOC_SESSION_ID to your session cookie value to run ./gradlew downloadInputs that is going to download all already available inputs.