commit 5081ea9a0f5bb09023ae957f22b1c79f40ac87db · treybastian.com/advent-of-code

+49
2024/day_02.ml
···

       1
       1
       +
       let filename = "./day_02_input.txt"

     

       2
       2
       +
       let try_read ic = try Some (input_line ic) with End_of_file -> None

     

       3
       3
       +
       

     

       4
       4
       +
       let is_values_safe a b direction =

     

       5
       5
       +
         match direction with

     

       6
       6
       +
         | "up" -> a < b && abs (a - b) < 4

     

       7
       7
       +
         | "down" -> a > b && abs (a - b) < 4

     

       8
       8
       +
         | _ -> false

     

       9
       9
       +
       

     

       10
       10
       +
       let direction a b = if a < b then "up" else "down"

     

       11
       11
       +
       

     

       12
       12
       +
       let is_line_safe list =

     

       13
       13
       +
         let a, b = (List.hd list, List.tl list |> List.hd) in

     

       14
       14
       +
         let direction = direction a b in

     

       15
       15
       +
         List.fold_left

     

       16
       16
       +
           (fun (acc, prev) x ->

     

       17
       17
       +
             if prev > -1 then (acc && is_values_safe prev x direction, x) else (acc, x))

     

       18
       18
       +
           (true, -1) list

     

       19
       19
       +
         |> fst

     

       20
       20
       +
       

     

       21
       21
       +
       let is_line_safe_part_2 list =

     

       22
       22
       +
         List.mapi

     

       23
       23
       +
           (fun i _ -> List.filteri (fun j _ -> j <> i) list |> is_line_safe)

     

       24
       24
       +
           list

     

       25
       25
       +
         |> List.exists (fun x -> x)

     

       26
       26
       +
       

     

       27
       27
       +
       let calculate_safe_score ic is_line_safe =

     

       28
       28
       +
         let rec calculate acc =

     

       29
       29
       +
           match try_read ic with

     

       30
       30
       +
           | Some line -> (

     

       31
       31
       +
               match

     

       32
       32
       +
                 is_line_safe (String.split_on_char ' ' line |> List.map int_of_string)

     

       33
       33
       +
               with

     

       34
       34
       +
               | true -> calculate (acc + 1)

     

       35
       35
       +
               | false -> calculate acc)

     

       36
       36
       +
           | None ->

     

       37
       37
       +
               close_in ic;

     

       38
       38
       +
               acc

     

       39
       39
       +
         in

     

       40
       40
       +
         calculate 0

     

       41
       41
       +
       

     

       42
       42
       +
       let () =

     

       43
       43
       +
         let ic = open_in filename in

     

       44
       44
       +
         calculate_safe_score ic is_line_safe

     

       45
       45
       +
         |> Printf.sprintf "Safe %d" |> print_endline;

     

       46
       46
       +
       

     

       47
       47
       +
         let ic = open_in filename in

     

       48
       48
       +
         calculate_safe_score ic is_line_safe_part_2

     

       49
       49
       +
         |> Printf.sprintf "Safe %d" |> print_endline