Initial version of the code tried to solve pt 1
using BFS, which took way too long even for the
test data.
After some fiddling with algebra with pen and paper,
I realized this 2 formulaes (using first example):
94 * b1 + 22 * b2 == 840
34 * b1 + 67 * b2 == 540
*b1 = button A presses
*b2 = button B presses
... could be rewritten to this single expression:
(94 + 34) * b1 + (22 + 67) * b2 = 840 * 540
I failed to remember the algebra for solving x than
y though, that I had to learn from the subreddit.
In the code, this is the ratio part.
Also, this solution using fractions is SICK.
https://www.reddit.com/r/adventofcode/comments/1hd4wda/comment/m1tz3nf/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button
Loooong time overdue. First drafts of the code
kept track of every id separately in a defaultdict.
This was not sustainable since the code examples
had some recurring ids, and after managing to
support the test cases the code was eay off for
the real puzzle input.
In the end, the whole code was deleted and replaced
by a BFS solution that expands the current regions
until it finds no more areas.
Got the trick to count all perimiters in an else clause
from a leaderboard placed youtuber.
