--- Day 15: Chiton ---
https://adventofcode.com/2021/day/15
For this one I had to implement a Heap and Dijkstra's algorithm. Not as bad as it sounds. Encoding grid coordinates for the 2D array was actually the larger source of bugs. And then to get part 2 working, i made the indexing even harder by calculating the values of the 25x enlarged cave. That was okay, but then to make a 500x500 have work, I could no longer use a list (max 200,000 elements) to track the costs so far, and had to split it into two list, which was ugly. Then I had to tune it so the visualization would still work for the 500x500 case. It's still not smooth.