aoc25_ocaml/lib/day1_improved.ml
2025-12-02 22:54:16 +01:00

103 lines
3.5 KiB
OCaml

(* Improved version of day1.ml with better code quality *)
let input = Reuse.split_lines "inputs/day1.txt"
(* Improved: Better function name and documentation *)
let parse_direction (s : string) : int =
if String.length s = 0 then
invalid_arg "Empty direction string"
else
let direction = s.[0] in
let distance_str = String.sub s 1 (String.length s - 1) in
let distance = int_of_string distance_str in
match direction with
| 'L' -> -distance (* Negative for left turns *)
| 'R' -> distance (* Positive for right turns *)
| _ -> invalid_arg ("Invalid direction: " ^ String.make 1 direction)
(* Improved: More descriptive function name *)
let count_if_at_origin (counter : int) (position : int) : int =
if position = 0 then counter + 1 else counter
(* Improved: Better function name and clearer logic *)
let normalize_position (position : int) (modulus : int) : int =
let result = position mod modulus in
if result >= 0 then result else result + modulus
(* Improved: More descriptive function name and clearer logic *)
let count_boundary_crossings (counter : int) (old_position : int) (movement : int) : int =
Printf.printf "Position %i, movement %i, current counter %i\n" old_position movement counter;
(* Count full rotations (every 100 units) *)
let full_rotations = abs movement / 100 in
let remaining_movement = movement mod 100 in
let new_position = old_position + remaining_movement in
(* Count boundary crossings *)
let boundary_crossings =
if (new_position >= 100 && old_position < 100) ||
(new_position <= 0 && old_position > 0) then 1 else 0
in
counter + full_rotations + boundary_crossings
(* Improved: More descriptive function names *)
let rec solve_with_origin_counting (movements : int list) (position : int) (counter : int) : int =
match movements with
| [] -> counter
| movement :: remaining ->
let new_position = normalize_position (position + movement) 100 in
solve_with_origin_counting remaining new_position (count_if_at_origin counter new_position)
let rec solve_with_boundary_counting (movements : int list) (position : int) (counter : int) : int =
match movements with
| [] -> counter
| movement :: remaining ->
let new_position = normalize_position (position + movement) 100 in
let new_counter = count_boundary_crossings counter position movement in
solve_with_boundary_counting remaining new_position new_counter
(* Improved: Clear, descriptive function names *)
let solve_part1 (lines : string list) : int =
let movements = List.map parse_direction lines in
solve_with_origin_counting movements 50 0
let solve_part2 (lines : string list) : int =
let movements = List.map parse_direction lines in
solve_with_boundary_counting movements 50 0
(* Main solutions *)
let day1_part1 : int = solve_part1 input
let day1_part2 : int = solve_part2 input
(* Improved: Better test organization *)
module Tests = struct
let test_input = "L268
L30
R48
L5
R60
L55
L1
L99
R14
L82"
let test_lines = String.split_on_char '\n' test_input
let run_tests () =
let part1_result = solve_part1 test_lines in
let part2_result = solve_part2 test_lines in
if part1_result <> 3 then
failwith ("Part 1 test failed: expected 3, got " ^ string_of_int part1_result);
if part2_result <> 8 then
failwith ("Part 2 test failed: expected 8, got " ^ string_of_int part2_result);
Printf.printf "All tests passed!\n"
end
(* Run tests *)
let () = Tests.run_tests ()