SudokuPX (SudokuP + Diagonal)

For fans of Killer Sudoku, Samurai Sudoku and other variants

Re: SudokuPX (SudokuP + Diagonal)

Postby Leren » Thu Sep 06, 2018 11:35 am

The latest news I have on the SudokuPX front is that Mathimagics now has a stash of 206,059 puzzles solving to 88,114 EDPX grids. The number is rising slowly, as MM is working furiously on the SudokuP 12 clue project, and I'm finding about a hundred puzzles a day with my spreadsheet approach, although I suspect that if MM got back on this project the number of puzzles would rise very quickly. The 9 clue puzzle count is stalled at 3.

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Re: SudokuPX (SudokuP + Diagonal)

Postby creint » Thu Sep 06, 2018 9:07 pm

eleven wrote:I guess your single chains can't resolve single digit patterns like the ones i posted above.

With your hardest step:
An ALS gets reduced by a chain, but that chains contains 2 subchains that each result in a reducing it to a Locked set.
For the extra eliminations in cell r9c9, you use yet another chain to proof 3 or 5.
How far should a solver go, with depth or trying extra chains?

I did not use sets in my solving net nor did i use subchains, so it would have never found this. But still my solver would solve up to SE 9, i think.
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Re: SudokuPX (SudokuP + Diagonal)

Postby Mathimagics » Thu Sep 06, 2018 11:47 pm

OK, we started with SudokuP, found the absolute minimal puzzles (11 clues), and these turned out to be P&P solvable without too much difficulty.

But when we add the X constraints, we find that 9-clues is the new minimum, and these puzzles are clearly challenging.

I think that tarek has confirmed that the same situation applies to SudokuW (Windoku), which after all is simply SudokuP with a different set of "windows" (PSET's). The 9-clue puzzle I posted there there is similarly challenging, it seems.

One of the reasons I find Kakuro so absorbing is that it has enormous range in difficulty levels (wrt P&P solving), from easy to impossible. I conjectured once that Sudoku was less interesting because it had a much narrower range.

But here we have demonstrated, I think, that these variants extend the difficulty range considerably.

I think this is a good thing! 8-)
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