Files
2019/inputs/20s1.txt
Parnic 34e6055782 Day 20 solution
Part 1 was pretty much just day 18 again, but without doors and with an input data parsing skill check. I simplified day 18 and went with a basic Dijkstra algorithm after the DFS to crawl the maze which solved this just fine.

Part 2 messed me up more than I was expecting. The key feature for part 2 is changing up what the Dijkstra solver views as an "adjacent" node and injecting the appropriate depth as we traverse inner/outer portals. The main thing that tripped me up here from part 1 was that I needed to be carrying more data along with portals than just their locations, and I could no longer get away with storing the portals as pairs of their inner/outer locations, so a small refactor was needed. Once I made those corrections, it was mostly a matter of ironing out the "get neighbors" function to adhere to part 2's rules, which took me a lot of debugging to get just right.

Part 2 still took me longer than I'd care to admit. I had problems wrapping my head around the problem.
2022-06-22 23:35:29 -05:00

19 lines
417 B
Plaintext

A
A
#######.#########
#######.........#
#######.#######.#
#######.#######.#
#######.#######.#
##### B ###.#
BC...## C ###.#
##.## ###.#
##...DE F ###.#
##### G ###.#
#########.#####.#
DE..#######...###.#
#.#########.###.#
FG..#########.....#
###########.#####
Z
Z