day 18 is simple as the search space is small so for part 2 we can just
do the opposite of part 1 and scan through all empty spaces surrounding
the droplet
Merge branch 'master' of github.com:peter-tanner/advent-of-code-2022
day 18 is simple as the search space is small so for part 2 we can just
do the opposite of part 1 and scan through all empty spaces surrounding
the droplet
got both answers first try!
slow af solution. I hoped that keeping the solution O(j) would be quick
enough and seems like it is, takes around ~10 seconds to complete but
that is achievable. For each j it breaks the row into intervals
generated based on the taxicab radius. The intervals are simplified
by sorting and joining.
this is the part where the challenges start to get hard. implementing
the naive solution for part 1 did not take much time. used a hashset
since it's easier than using arrays, but slightly less performant. I
expected the naive solution would not work for part 2 due to the size of
the problem but it still worked, although it did take a few seconds to
finish. the solution i would have used if part 2 took too long would be
to trace some 45* rays from the end points of horizontal beams and
subtract the area inside from the largest sand triangle.
had a lot of issues with this one. I understood i needed dijkstra's from
the start because the second part would probably increase the complexity,
but I did not read the question enough and did not realize that we could
go down by any amount, only increases in elevation were limited. This
resulted in a lot of time being wasted on debug code to print the grid.
Cool puzzle requiring a bit of thinking for the second part. Had a lot
of issues with rust's moving system in this one, had to read some docs
again. I think I understand it better after this one.
i learnt more about how memory safety in rust works and why we need to
split a vector when mutating it in two locations to ensure they don't
conflict. makes a lot of sense to me now. also learnt that tuples can be
used in `match`, makes stuff really clean.
Have to learn how the various pointer types work for rust, this was the
main blocker preventing me from creating a recursive data structure to
store the tree.
