Ok, by my reckoning
- there are 330,845 ED SudokuNC grids
- there are 12,263 ED SudokuNC+ grids
Despite the dodgy solver, it did produce all the valid solutions, just some unwanted rubbish as well. Once we tossed out the trash, and verified the counts, then generated the CF (Canonical Form) for each valid grid, then removed the duplicates, only the ED grids were left.
Full ED grid listings available on request (PM me with an email address).
ED counts are of course provisional, subject to the normal requirement of some independent verification.
[
EDIT] Oh dear, made a hash of it. All my CF functions to date have normalised the grid isomorphisms before determining which is smallest lexically, but of course we can't do that here, it totally kills the NC property. Revised figures updated above. (Thanks
blue!
)
[
EDIT #2] Owing to a bug in my NC+ CF function, the NC+ figure above was wrong, the count above now agrees with that reported by
blue