What is SimpleSoduko really telling me?

elroy

SimpleSoduko is neat although admittedly the only one I have --
I used it to (auto)crack following solveable puzzle but it still required GUESSWORK, got lots of "NO HINTS AVAILABLE" messages until things got rolling (it does have at least ONE solution)..
>
I know SS's prime purpose isn't solving imported puzzles, but what is SimpleSoduko telling me about such a puzzle -- that it's perhaps invalid, maybe with more than one solution, or simply that it's a hard one to solve

>
8__4__6__
_3__6__7_
__7_____2
1__6__3__
_7__4__8_
__3__9__6
___8__4__
_9__5__2_
__1_____5 (courtesy of tso at sudoku.com forum demonstating puzzles with (perhaps none) bi-valued candidates (this has just one))

TIA -- elroy Confused

(don't know where else to post such product-specific question)

Henk · Posted: Thu Mar 16, 2006 3:42 pm Post subject:

For puzzles that need more advanced techniques, Simple Sudoku probably isn't the best choice. You might want to look at one of these programs:

Into Sudoku (My own program, supports most techniques until triple implication chains, and it contains an quick overview of whats in the puzzle)
Sudoku Cue (I didn't test the latest version because I do not have the .Net framework, but it has some nice techniques in it)
Sudoku Susser (Pretty good, but it uses a lot of guessing techniques like nishio and tabling)

Just google on the name, and you will find the program...

But neither of these programs can break the puzzle you posted with pure logic only. This requires an extremely advanced and complete arsenal of techniques.
_________________
Generate and solve Sudoku puzzles with Into Sudoku!

elroy · Posted: Thu Mar 16, 2006 4:46 pm Post subject:

Many many thanks, Henk, I'll certainly follow up your input.

BTW, I've subsequently discovered author (Vidar) of that puzzle (it's called Monster#2) from another forum&thread (if interested): http://www.sudoku.com/forums/viewtopic.php?t=3499

It all making sense NOW, thank you very much again. -- elroy Embarassed

tarek · Posted: Thu Mar 16, 2006 4:59 pm Post subject:

I remeber this one from vidarino,

It is an example of a NO nonesense puzzle, straight into business....

this is the only step that my solver struggled with (one contradiction elimination was required)........

Ruud · Site Admin

There are 5 backdoors (magic cells) in this one:

R8C3, R8C6, R8C7, R9C2, R9C7

I cannot find a single step that isolates any one of them. 12 ugly chains required by my solver...

Ruud.

vidarino · Posted: Fri Mar 17, 2006 6:07 pm Post subject:

Glad you like my puzzle. Smile

It's a tricky bastard, allright...

My solver opens with a few nice loops with groups, the first two being;