Revenge, blast from the past etc!
Had to learn Dijkstra's for this one. Was as stuck
as one can be on AOC. This stopped my progress
2023, and kept me busy at least 20-30h this year
(2024) as well. I never came past part 1, but got
part 2 in minutes when I hit home.
Turns out the initial queue was to blame, after
studying Dijkstras, reading hints on the subreddit
and tutorials in blogs. I was off-by-1 in costs,
since I misplaced a read from the grid.
I also struggled a really, really long time with
a bug where I resetted the steps to aggresively.
What helped me to figure it out was to create
simpler test case grids and step-debug them.
Example 1:
241
321
should give a least heat loss of 6 in pt1.
Example 2:
11199
12199
99199
99131
99111
should give a least heat loss of 9 in pt2.
Anders Englöf Ytterström
178d96494a