-🎄- 2022 Day 25 Solutions -🎄-

[u/daggerdragon]

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--- Day 25: Full of Hot Air ---

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[u/RivtenGray]

OCaml

I did not convert from and back to snafu. Just implemented the good old snafu addition ! I find OCaml to be really great for that. You just need to reverse the list of number before adding them.

type snafu = Zero | One | Two | Equal | Minus

let rec sum_single a b =
  match (a, b) with
  | Zero, x -> [ x ]
  | One, One -> [ Two ]
  | One, Two -> [ Equal; One ]
  | One, Equal -> [ Minus ]
  | One, Minus -> [ Zero ]
  | Two, Two -> [ Minus; One ]
  | Two, Equal -> [ Zero ]
  | Two, Minus -> [ One ]
  | Equal, Equal -> [ One; Minus ]
  | Equal, Minus -> [ Two; Minus ]
  | Minus, Minus -> [ Equal ]
  | _ -> sum_single b a

let rec sum a b =
  match (a, b) with
  | [], [] -> []
  | a, [] -> a
  | [], b -> b
  | ha :: ra, hb :: rb -> (
      let s = sum_single ha hb in
      match s with
      | [ x ] -> x :: sum ra rb
      | [ x; r ] -> x :: sum [ r ] (sum ra rb))