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open Batteries
open Mathlib
let pos = 1_000_000
let tokens = [0;1;2;3;4;5;6;7;8;9]
let rec permute tokens acc pos =
match tokens with
[] -> List.rev (acc)
| [x] -> List.rev (x :: acc)
| t ->
let len = List.length t in
let sub_count = factorial (len-1) in
let token_pos = pos / sub_count
and next_pos = pos mod sub_count in
let found = List.at t token_pos in
Printf.printf "subperm %d: %d (pos %d clust %d) next: %d\n" pos found token_pos sub_count next_pos;
permute (List.remove t found) (found::acc) next_pos
let () =
permute tokens [] (pos-1) |> List.iter (fun i -> print_int i);
print_newline()
|
