open Printf;;
open String;;

let rec build_list in_file =
  try
    let line = input_line in_file in
    line ::  build_list(in_file)
  with End_of_file ->
    close_in in_file;
    []

let is_not_empty lst = 
  match lst with
  | [] -> false 
  | _  -> true

let rec parse_list (l1, l2) str =
  let list1 = (List.filter (fun a -> length a != 0) (String.split_on_char ' ' str)) in
  let list_of_int = List.map int_of_string list1 in
  match list_of_int with
  | e1 :: e2 :: _ -> (e1 :: l1, e2 :: l2)
  | _ -> failwith "Not enough ints in a line"

let rec count_and_remove value acc lst =
  match lst with
  | n :: tail ->
    if n < value then
      count_and_remove value acc tail 
    else if n == value then
      count_and_remove value (acc + 1) tail
    else
      (acc, lst)
  | _ -> (acc, lst)

let rec get_list_similarity acc l1 l2 =
  match l1 with
  | n :: tail1 ->
    let (c1, l1_new) = count_and_remove n 1 tail1 in
    let (c2, l2_new) = count_and_remove n 0 l2 in
    get_list_similarity (acc + n * c1 * c2) l1_new l2_new
  | _ -> acc

let () =
  let f = open_in "input.txt" in
  let lst = build_list f in
  let (l1, l2) = List.fold_left parse_list ([], []) lst in
  let l1_sorted = List.sort Int.compare l1 in
  let l2_sorted = List.sort Int.compare l2 in
  let result = List.fold_left Int.add 0 (List.map2 (fun a b -> Int.abs(a - b)) l1_sorted l2_sorted) in
  let result2 = get_list_similarity 0 l1_sorted l2_sorted in
  printf "%d\n" result;
  printf "%d\n" result2