diff options
Diffstat (limited to '2025')
| -rw-r--r-- | 2025/ocaml/lib/domain/d03p01.ml | 45 |
1 files changed, 30 insertions, 15 deletions
diff --git a/2025/ocaml/lib/domain/d03p01.ml b/2025/ocaml/lib/domain/d03p01.ml index e951d4b..1367712 100644 --- a/2025/ocaml/lib/domain/d03p01.ml +++ b/2025/ocaml/lib/domain/d03p01.ml @@ -28,6 +28,9 @@ module BatteryBank : sig type t val highest_joltage : t -> int + (** [highest_joltage bb] is an integer created from the two highest + digits in [bb]. + Raises: [Assert_failure] if [bb] is empty. *) val of_string : string -> t @@ -40,44 +43,56 @@ end = struct type t = Battery.t list let rec highest_joltage bb = + assert (List.length bb > 0) ; match highest_joltage_aux (None, None) bb with | None, None -> 0 | Some x, Some y -> int_of_string (Battery.to_string x ^ Battery.to_string y) | _ -> - failwith "highest_joltage_aux must result in two digits" + failwith "highest_joltage must be two digits" and highest_joltage_aux acc = function | [] -> acc + | [elt] -> ( + match acc with + | None, None -> + (Some (Battery.of_int 0), Some elt) + | Some first, None -> + (Some first, Some elt) + | None, Some second -> + (Some second, Some elt) + | Some first, Some second -> + if elt > second then (Some first, Some elt) + else (Some first, Some second) ) | h :: t -> highest_joltage_aux ( match acc with | None, None -> (Some h, None) | Some first, None -> - (Some first, Some h) + let second = Battery.of_int 0 in + swap_if_higher first second h | Some first, Some second -> - swap_if_higher first second h (List.length t = 0) + swap_if_higher first second h | _ -> failwith "this branch should be impossible" ) t - and swap_if_higher first second considering is_end = + and swap_if_higher first second considering = + assert (first >= second) ; let c_gt_f = Battery.compare considering first = 1 in let c_gt_s = Battery.compare considering second = 1 in - let f_gt_s = Battery.compare first second = 1 in - if c_gt_f && c_gt_s && f_gt_s then - if is_end then (Some first, Some considering) else (Some considering, None) - else if (not c_gt_f) && c_gt_s && f_gt_s then (Some first, Some considering) - else if c_gt_f && c_gt_s && not f_gt_s then - if is_end then (Some second, Some considering) - else (Some considering, None) - else if (not c_gt_f) && (not c_gt_s) && f_gt_s then (Some first, Some second) - else if c_gt_f && (not c_gt_s) && not f_gt_s then - (Some second, Some considering) - else (Some first, Some second) + match (c_gt_f, c_gt_s) with + | true, true -> + (Some considering, None) + | false, true -> + (Some first, Some considering) + | true, false -> + failwith "[second] should never be greater than [first]" + | false, false -> + (Some first, Some second) let of_string s = s |> String.to_seq |