This repository contains my solutions to Advent of Code 2023. I have chosen to solve those problems using Go (and learn it in the process). I may solve some problems with C/C++ if I feel like it. If a problem will prove too hard to solve with those (since I do not know them all that great) I will probably default to Python.

• Day 1
  • Part 1
  • Part 2
• Day 2
  • Part 1
  • Part 2
• Day 3
  • Part 1
  • Part 2
• Day 4
  • Part 1
  • Part 2
• Day 5
  • Part 1
  • Part 2
• Day 6
  • Part 1
  • Part 2

The first part of the first day was pretty easy. I just had to read the input file and find the first and last integer in each line of the input. I used the ioutil package to read the file and wrote my own func to split input lines. I then wrote another function to find the first and last integers by simple for loops.

The second part was a bit more tricky. I had to find integers spelled out as their word representation. My initial approach with replacing the words with strings.ReplaceAll did not work because of edge cases such as:

"twone" -> "2ne" instead of "21"

which proved to be a problem when calculating the sum. I wrote a quick program in Python since I am more familiar with it to solve it quickly by using for loops to iterate over string char by char and replacing the words with their number representation while leaving the last letter of the word intact. This proved to be a good enough solution for the problem. I then rewrote the solution in Go. My first approach can be seen in helper.go file.

The first part took me a little bit of time, mostly because of a weird quirk of splitting in Go - when you split the following string " 2 red" it splits into 3 elements: "", "2" and "red". Other than that, it was pretty straigthforward. I got to know the OOP side of Go (if you can call it that) a bit better.

The second part was actually fairly easy, after I figured out the splitting in the previous part. I just added some new functions to calculate minimum number of cubes per color and called them in corresponding for loops. Easy peasy

This one was hard enough for me to default to Python. I added a function to get surroundings of each number and then looked for matching regexes to find correct numbers with re module. Did not thing it would actually work but it did. After that, it was doable.

This one was not much harder after I figured out how to use regexes properly. Added a function to find gears (ergo *) which was done in the most straightforward way possible. After I had some fun with timer wrappers using time module and packed both parts into one function.

Did not work in Go, so defaulted to Python again (I know, I know). Nothing special really, just parsing input, packing first part of each card into a set and checking second part for matchings.

A bit more tricky, since kind of a recursive formula was needed. In the end, I just used a dictionary to update counts as I go (also reduced time complexity to O(n) from O(n^2)) this way. Added a class to contain Cards, since I wanted their id anyways.

So, basically mapping things efficiently. Tried brute forcing, my idea for that is in test.py. It worked for part 1, but was not efficient enough for part 2.

For second part, this did not work, so I added a Transformer class and figured out applying trasformations to a range efficiently. A bit inspired by solution found in subreddit.

Probably the easiest one so far. Just had to parse input find possible solutions so brute force worked just fine.

Same code as part 1, achieved it by just changing the input format in file. Could quite easily adjust the parsing as well.