and for my non-macro solution!
Here's where the magic happens, something like 23,000 characters in that Multi-Row Formula tool checking the prior 200 rows:
Also started off with a macro that worked beautifully for the first 10 iterations, but grinded to a halt at around iteration 23.
Thanks everyone for the suggestion of looking only at the pairs of letters and their resulting new letters. Once I wrapped my head around how to solve, building the macro was pretty easy.
My brute forth macro was failed...
Community member's tips helped me a lot!
Brute forth macro for star1
GitHub
https://github.com/AkimasaKajitani/AdventOfCode/tree/main/2021
Like everyone else - I first started with brute-force build-out of the full string.
But the 40 iteration run crashed Alteryx - the string is too long for Alteryx strings.
Also - note the super-cool Pairs icon for this macro
And here is the pairs macro
Ahhhhh finally got Part 2!! Took several days of noodling on it, and scrolling through tips from Community + ACEs (I think @afv2688 was the first to point me in the right direction, THANK YOU!!), but it finally clicked.
Part 1 Macro:
Part 2 Macro:
I find it incredibly interesting that, with the possible exception of the interface/macro tools, 95% of these AoC workflows can be solved with the basic tools in the Favorites category. So powerful!!
Cheers!
NJ
for counting it take either one letter of original pair and the new letter, and do not forget to add back the last digit.
Like everyone else my macro for Part 1 could not compute for Part 2 due to not having a super computer, so I had to pivot and thankfully it worked very well
Macro: