45 lines
1.1 KiB
OCaml
45 lines
1.1 KiB
OCaml
open Scanf
|
|
|
|
let handle_line line = sscanf line "%d %d" (fun num1 num2 -> (num1, num2))
|
|
let sort_list l = List.sort compare l
|
|
|
|
let build_lists lines =
|
|
let rec loop lines l1 l2 =
|
|
match lines with
|
|
| [] -> (l1, l2)
|
|
| head :: tail ->
|
|
let num1, num2 = handle_line head in
|
|
loop tail (l1 @ [ num1 ]) (l2 @ [ num2 ])
|
|
in
|
|
loop lines [] [] |> fun (l1, l2) -> (sort_list l1, sort_list l2)
|
|
|
|
let find_occurances l item =
|
|
let rec loop l item acc =
|
|
match l with
|
|
| [] -> acc
|
|
| head :: tail ->
|
|
if head == item then loop tail item (acc + 1) else loop tail item acc
|
|
in
|
|
loop l item 0
|
|
|
|
let solve lines =
|
|
let rec distance l1 l2 acc =
|
|
match (l1, l2) with
|
|
| [], [] -> acc
|
|
| h1 :: t1, h2 :: t2 ->
|
|
distance t1 t2 (acc + if h1 > h2 then h1 - h2 else h2 - h1)
|
|
| _, _ -> acc
|
|
in
|
|
|
|
let l1, l2 = build_lists lines in
|
|
let part1 = distance l1 l2 0 in
|
|
|
|
let rec similarity l1 l2 acc =
|
|
match l1 with
|
|
| [] -> acc
|
|
| head :: tail -> similarity tail l2 (acc + (head * find_occurances l2 head))
|
|
in
|
|
|
|
let part2 = similarity l1 l2 0 in
|
|
(part1, part2)
|