Advent-of-Code-2021 VS adventofcode

I totally recommend trying - it's going to be a lot of fun and you'll understand the structure better. I'm not a pro and I never studied CS - that's just my experience from last year (day 18).

I keep a diary of what I learned, revised or improved at in my repo.

Python - needs over 45 seconds but WORKS, which is good enough for me after a couple of days, especially given the fact that I can spend at most 1-2 hours a day solving this... The ugliest part are probably the hard-coded distances from rooms to corridors and vice versa, but what the heck, it works.

For reference, here's my work-in-progress code (Python). But most imporatntly I want to describe my line of thinking :

As a complete hobbyist, I was glad I figured out this had something to do with binary trees. It took about an hour to design everything on paper. Then I started to code it...and then debug...and four hours later I finally arrived at this solution.

Python

I'm not sure what kind of brainfog descended on me this morning. After part 1 I instantly knew I should just count the pairs and update their numbers but somehow couldn't figure out how to do it. It took me almost an hour before it dawned on me that...wait for it...a pair splits into two pairs. After that and some off-by-one debugging I came up with this solution. Defaultdict for the win.

Python - two alternative solutions (lines 25-65 and 68-106, not including the parser)

This is not my first visualisation but for the first time I decided to share one here. It looks worse on screen due to flickering (I print the board and clear the screen after each step). Here's the code.

Anyway, here's my stack-based Python solution. It could be made way shorter because there's actually no need to store data separately about valid lines (valid == not corrupt and empty stack), but I thought the verbose approach makes the solution a bit more understandable.

Part one went fairly fast, but spent quite some time on getting part two right. I settled on the approach of just iterating over the grid and using a boolean to see if I had to count elements or not. However, I had some issues figuring out when to swap, this post by /u/rogual helped me figure it out. After that I lost quite some time on an error that only occurred with my input, not with the example input. It turned out that my loop (which I take form my p1 solution) didn't include the start node, which caused all sorts of counting issues.

[Language: Elixir] https://github.com/mathsaey/adventofcode/blob/master/lib/2023/4.ex