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|
open Dial
let err_empty_input = "input is empty"
let rec input_to_lines input =
let lines =
String.split_on_char '\n' input |> List.filter (fun l -> l <> "")
in
pp_lines lines ; lines
and pp_lines = function
| [] ->
()
| h :: t ->
Logs.debug (fun m -> m "Line=%s" h) ;
pp_lines t
let parse_line line =
Scanf.sscanf line "%c%d" (fun d n ->
match d with
| 'L' ->
Dial.Left n
| 'R' ->
Dial.Right n
| _ ->
failwith "invalid direction" )
let lines_to_turns =
List.map (fun (l : string) ->
Logs.debug (fun m -> m "parsing %s into turn" l) ;
let turn = parse_line l in
Logs.debug (fun m -> m "%s" (Dial.pp_direction turn)) ;
turn )
let rec turn_aux count current = function
| [] ->
count
| h :: t ->
let current' = Dial.turn current h in
Logs.debug (fun m -> m "dial at %d" (Dial.to_int current')) ;
if Dial.to_int current' = 0 then turn_aux (count + 1) current' t
else turn_aux count current' t
let turn current = turn_aux 0 current
let solve input () =
if input = "" then Error err_empty_input
else
let lines = input_to_lines input in
let turns = lines_to_turns lines in
let start = Dial.start in
let answer = turn start turns in
Ok answer
|
