Improve performance on year2025::day09

[Pencilcaseman]

Both part 1 and part 2 require the input to be sorted, but currently they're sorted independently and in a different order.

Transposing part 1 to work with an input sorted by y first to match part 2 allows you to sort the tiles only once and avoid a couple copies.

Also, using u32s in place of u64s where possible makes things a touch faster.

Overall, this makes the solution ~15% faster on my machine (M2 Max)

Does it make more sense to refactor part 2 to work with x-ordered tiles?
EDIT: Part 2 is twice as fast with the x-ordered (transposed) processing order due to the structure of the input, so sorting by (y, x) instead of (x, y) makes sense.

[maneatingape]

Nice improvement! I get a ~20% speedup (49µs => 40µs).

[Pencilcaseman]

Thanks! I had to cheat and take a look at your solution to solve this one, so I'm glad I could help somehow