feat(2025d1p2): implement solution to problem

2 files changed, 55 insertions, 0 deletions

diff --git a/2025/ocaml/lib/application/d01p02.ml b/2025/ocaml/lib/application/d01p02.ml
new file mode 100644
index 0000000..6f935a4
--- /dev/null
+++ b/2025/ocaml/lib/application/d01p02.ml
@@ -0,0 +1,51 @@
+open Domain.D01p02
+
+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 dial = function
+  | [] ->
+      count
+  | h :: t -> (
+      let dial_and_count = Turner.turn dial count h in
+      match dial_and_count with
+      | dial', count' ->
+          Logs.debug (fun m ->
+              m "(dial=%d, count=%d)" (Dial.to_int dial') count' ) ;
+          turn_aux count' dial' t )
+
+let turn current = turn_aux 0 current
+
+let solve input () =
+  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
+  answer
diff --git a/2025/ocaml/lib/application/d01p02.mli b/2025/ocaml/lib/application/d01p02.mli
new file mode 100644
index 0000000..33aa63f
--- /dev/null
+++ b/2025/ocaml/lib/application/d01p02.mli
@@ -0,0 +1,4 @@
+val solve : string -> unit -> int
+(** [solve input ()] is the solution for the second part of the first day of advent of code 2025 for [input].
+    The solution for an empty input is 0.
+    Requires: [input] to be a multiline string using `\n` as it's line separator. *)