diff options
Diffstat (limited to 'ocaml/lib/year2025/day04/part01/solver.ml')
| -rw-r--r-- | ocaml/lib/year2025/day04/part01/solver.ml | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/ocaml/lib/year2025/day04/part01/solver.ml b/ocaml/lib/year2025/day04/part01/solver.ml new file mode 100644 index 0000000..7cc54f6 --- /dev/null +++ b/ocaml/lib/year2025/day04/part01/solver.ml @@ -0,0 +1,48 @@ +let err_empty_input = "input is empty" + +let rec solve input () = + if input = "" then Error err_empty_input + else + let matrix = Shared.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 = + Shared.Matrix.M.get_valid_neighbours matrix x y + in + let neighbours = + List.map + (fun (x', y') -> Shared.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 ) |