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
Anders Englöf Ytterström
1e807b5daf