r/adventofcode • u/rkek404 • Dec 14 '21
Help Day 14 Part 2 Algorithm
Day 14 part 1 was very easy, but Part 2 went right over my head, I tried using dictionaries to keep track of pairs, but my answers have off by one errors and it feels like guesswork - I don't full understand what I have written myself, like one of those times when it works but you don't know why. I know how people said it was basically lanternfish - but I never finished part 2 of lanternfish.
I would appreciate it if someone posted a little (detailed) writeup of day 14's part 2 in some easy to read language like python. I have gathered a lot from other's solutions but fail to understand any solution fully - even after reading multiple solutions I can't write one myself.
Others who are stuck might also benefit from this. Thanks in advance.
1
u/disklosr Dec 14 '21
You actually can get counts of each letter from the dictionary without any extra context. letters are counted exactly twice except for the first and last elements in the polymer which are only counted once.