82 lines
2.8 KiB
OCaml
82 lines
2.8 KiB
OCaml
let input = Reuse.split "inputs/day02.txt" ','
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let is_valid ((start, ending): string * string) : bool =
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let start_length = String.length start in
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let end_length = String.length ending in
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let filtered_out = start_length mod 2 != 0 && end_length mod 2 != 0 && start_length == end_length in
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not filtered_out
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let generate_tuple (value : string) : (string * string) =
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let split = String.split_on_char '-' value in
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match split with
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| first :: second :: [] -> (first, second)
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| _ -> failwith("Expected exactly 2 values in list entry" ^ value)
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let generate_pairs (inputs: string list) : (string * string ) list =
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List.map generate_tuple inputs
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let is_invalid (number: int) : bool =
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let number_string = string_of_int number in
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let length = String.length number_string in
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let is_even = length mod 2 == 0 in
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let half = length / 2 in
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let first_part = String.sub number_string 0 half in
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let last_part = String.sub number_string half half in
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let invalid = is_even && first_part = last_part in
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invalid
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let is_invalid_2 (number: int) : bool =
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let number_string = string_of_int number in
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let pattern = Str.regexp "\\(.+\\)\\1+$" in
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Str.string_match pattern number_string 0
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let calculate_for_line ((start, ending) : (string * string)) (inv: int -> bool) : int =
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let start_number = int_of_string start in
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let end_number = int_of_string ending in
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let rec loop i acc =
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if i > end_number then acc
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else loop (i + 1) (acc + if inv i then i else 0)
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in
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loop start_number 0
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let calculate_invalidities entries inv =
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List.fold_left (fun acc entry -> acc + calculate_for_line entry inv) 0 entries
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let solve_part1 (inputs: string list) : int =
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let inputs = generate_pairs inputs in
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let filtered = List.filter is_valid inputs in
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calculate_invalidities filtered is_invalid
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let solve_part2 (inputs: string list) : int =
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let inputs = generate_pairs inputs in
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calculate_invalidities inputs is_invalid_2
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let day2_part1 : int =
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solve_part1 input
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let day2_part2 : int =
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solve_part2 input
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module Tests = struct
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let test_input = "11-22,95-115,998-1012,1188511880-1188511890,222220-222224,1698522-1698528,446443-446449,38593856-38593862,565653-565659,824824821-824824827,2121212118-2121212124"
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let test_lines = String.split_on_char ',' test_input
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let run_tests () =
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let part1_result = solve_part1 test_lines in
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let part2_result = solve_part2 test_lines in
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if part1_result <> 1227775554 then
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failwith ("Day 2 Part 1 test failed: expected 1227775554, got " ^ string_of_int part1_result);
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if part2_result <> 4174379265 then
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failwith ("Day 2 Part 2 test failed: expected 4174379265, got " ^ string_of_int part2_result);
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Printf.printf "All day 2 tests passed!\n"
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end
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let () = Tests.run_tests()
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