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authorDJ O'Leary <dijitol@proton.me>2026-06-26 18:04:09 +0200
committerDJ O'Leary <dijitol@proton.me>2026-06-26 18:04:09 +0200
commit6d8fb621d1e93b83786890d6d9cb6f0d8defa8ae (patch)
tree17c90d3984c114aa023600cc5bec6f6004b02243 /ocaml/lib/application/d04p01.ml
parentad4ea5ca4bc9f7540ee1d6a4fa2d881709dc6459 (diff)
refactor!: invert repo directory structure
now is language first
Diffstat (limited to 'ocaml/lib/application/d04p01.ml')
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diff --git a/ocaml/lib/application/d04p01.ml b/ocaml/lib/application/d04p01.ml
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+open Domain
+
+let err_empty_input = "input is empty"
+
+let rec solve input () =
+ if input = "" then Error err_empty_input
+ else
+ let matrix = Matrix.M.of_string input in
+ let count_paper lst = List.length @@ List.filter (fun c -> c <> ".") lst in
+ let accessible_rolls_of_paper = ref 0 in
+ for y = 0 to Array.length matrix - 1 do
+ for x = 0 to Array.length matrix.(y) - 1 do
+ if matrix.(y).(x) = "." then ()
+ else
+ let neighbour_coords = Matrix.M.get_valid_neighbours matrix x y in
+ let neighbours =
+ List.map
+ (fun (x', y') -> Matrix.M.get matrix x' y')
+ neighbour_coords
+ in
+ let paper_count = count_paper neighbours in
+ let is_accessible = paper_count < 4 in
+ if is_accessible then
+ accessible_rolls_of_paper := !accessible_rolls_of_paper + 1 ;
+ print_iteration_debug_msg x y neighbour_coords neighbours paper_count
+ is_accessible
+ done
+ done ;
+ Ok !accessible_rolls_of_paper
+
+and print_iteration_debug_msg x y neighbour_coords neighbours paper_count
+ is_accessible =
+ Logs.debug (fun m ->
+ m
+ "coords=(%d,%d) neighbour_coords=[%s] neighbours=[%s] paper=%d \
+ is_accessible=%B"
+ x y
+ (List.fold_left
+ (fun acc (x, y) ->
+ if acc = "" then
+ " (" ^ string_of_int x ^ "," ^ string_of_int y ^ "); "
+ else acc ^ "(" ^ string_of_int x ^ "," ^ string_of_int y ^ "); " )
+ "" neighbour_coords )
+ (List.fold_left
+ (fun acc neighbour ->
+ if acc = "" then " " ^ neighbour ^ "; " else acc ^ neighbour ^ "; " )
+ "" neighbours )
+ paper_count is_accessible )