all_units.ml

open Printf
    
module IntSet = Set.Make(struct type t = int let compare = compare end)
    
let compute (base: int) (units: int list): IntSet.t =
  printf "base: %d, (" base; List.iter (printf "%d, ") units; printf ")\n";

  let rec f (digits: IntSet.t) (new_digits: IntSet.t) =
    if IntSet.cardinal new_digits = 0
    then digits
    else begin
      (* printf "("; IntSet.iter (printf "%d, ") new_digits; printf ") "; *)
      let new_digits_now =
        IntSet.fold (fun n set ->
            (IntSet.fold (fun m set ->
                let t = (n + m) mod base in
                if IntSet.mem t digits then set else IntSet.add t set
            ) new_digits IntSet.empty) |> IntSet.union set
          ) digits IntSet.empty
      in f (IntSet.union digits new_digits) new_digits_now
    end
  in

  let digits = f (IntSet.singleton 0) (units |> IntSet.of_list) in
  (* print_newline(); *)
  printf "l: %d - " (IntSet.cardinal digits);
  IntSet.iter (printf "%d, ") digits; print_newline (); print_newline ();
  digits

let () =
  compute 42 [6];
  compute 42 [7];
  compute 42 [6; 7];
  let n = 29 in
  let store: IntSet.t ref array array = Array.init (n + 1) (
      fun _ -> Array.init (n + 1) (fun _ -> (ref IntSet.empty))) in
  for i = 2 to n do
    for j = 1 to (i - 1) do
      store.(i).(j) := compute i [j]
    done
  done;
  for i = 2 to n do
    for j = 1 to (i - 1) do
      for k = 1 to (i - 1) do
        let t = compute i [j; k; ] in
        let new_set = IntSet.union !(store.(i).(j)) !(store.(i).(k)) in
        if IntSet.cardinal t != IntSet.cardinal new_set then
          printf "===== !FAULT! =====\n";
      done
    done
  done;