I have added 'solve method F', aka X-wing, swordfish...

(www.sudokusolver.co.uk) to my solver, that reduced the number of puzzles

needing guesses to 5306, so I suppose that's it.

I haven't yet implemented it efficiently, so it was devastating for

performance - and solving thirteen puzzles more by pure logic (or should we

rather say without using any assumptions except that the puzzle is solvable,

uniquely or not?) isn't such a big step, I had hoped for more.

Cheers,

Daniel

Am Freitag, 14. April 2006 21:40 schrieb Chris Kuklewicz:

> > I believe if you change the representation of puzzles from [(pos,range)]

> > to an Array, you'll get a significant speedup

> >

> >>> yet because I only recently removed a logic bug that slowed down the

> >>> search instead of speading it up; ..). so the more interesting bit is

> >>> that our solvers disagree on which are the most difficult puzzles

> >>> (requiring the largest number of guesses):

> >>>

> >>> df

> >>> puzzles involving guesses: 5319

> >>

> >> If that's not a typo, I'm baffled. My original needed to guess in 5309

> >

> > Rot! Typo in _my_ previous message, 5319 is correct.

>

> After posting my cleaned up dancing links solver, I went back to my logical

> solver. I sent the 36628 line sudoku17 puzzle through it and it could

> solve 31322 of the puzzles, leaving 5306 resistant. I haven't check my

> algorithms against your code, but it does not seem like I do any

> spectacularly more clever.

>

> I don't have any time to clean up my code, but I may try turning off some

> steps to see if one of them gives my the same 5319 number you are seeing.

--

"In My Egotistical Opinion, most people's C programs should be

indented six feet downward and covered with dirt."

-- Blair P. Houghton

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