Day 18. See AOC.Solver for the types used in this module!

After completing the challenge, it is recommended to:

• Replace AOC.Prelude imports to specific modules (with explicit imports) for readability.
• Remove the -Wno-unused-imports and -Wno-unused-top-binds pragmas.
• Replace the partial type signatures underscores in the solution types _ :~> _ with the actual types of inputs and outputs of the solution. You can delete the type signatures completely and GHC will recommend what should go in place of the underscores.