AdventOfCode2021 VS adventofcode

Full program on GitHub.

Full program including code to deal with heaps, on GitHub.

Program I used for the above results

See my solution on GitHub.

Note also that you can solve this without a complexity dependency on n. Most solutions I have seen, including mine run in time O(tD), where t is the maximum value of a timer, and D the number of generation, requiring O(t) memory. (This is assuming we can do the required arithmetic operations in constant time, and each numbers require a fixed around of memory storage; if the number of fish gets huge, throw in an additional log n in the complexities, where n is the number of fish on the final day).

Based on my matrix exponentiation solution, here is a closed-form solution:

In my Perl solution of today (I assume, you mean 2021, Day 4), I read stuff in paragraph mode ($/ = "") which makes Perl split input on 2 or more newlines.

I considered doing that for my (Perl) solution, but given the cards are small, that seemed overkill.

Python implementation on GitHub

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