SudokuSolver Forum

Has anyone done this puzzle yet:

http://www.sudoku.com/boards/viewtopic. ... 4457#24457

Does it require anything more advanced than an X-wing? I'm stuck again (after several tries), and I'm not sure whether I'm missing something or I just don't know the required techniques yet.

The easiest way to know this is to run it through a solver. I just ran it through JSudoku, which reported:

Techniques used:
349 Naked Singles
164 Hidden Singles
50 Intersections
6 Naked Pairs
6 Naked Triplets
1 Naked Quads

_________________
Quis custodiet ipsos custodes?

Normal: [D  Y-m-d,  G:i]     PM->email: [D, d M Y H:i:s]

Silly me! That never occurred to me.



Hmmm. . . I must be missing something, then. I'll have to go through it again, and if I still don't see it, I'll post what I have, so others can take a look. I haven't hit any impossibilities (such as all candidates eliminated from a cell, etc.), but I got to the point that I couldn't find any more moves.

I didn't do it manually ....

What I would suggest is to check this puzzle using a solver tweaked to simulate closely your solving methods .....

If you solve using Pencilmarks ... Then my suuggestion is to paste dead end state to a solver (or here) to discuss.

If you are a manual solver ... Then with knowledge of your techniques ability, the next step can also be discussed from the the solution progress.

tarek

I would paste the Sudoku code into for instance JSudoku and then do single step solving (Solve > Deduce One Move = Ctrl+D) until JSduoku shows approximately what you currently have on paper, and then see what its next move is.

My personal guess is that you have a problem spotting the Naked Quad or one of the Naked Triplets.

Using a helper I normally have no problems spotting large Naked Subsets, unless they consist of only cells with two pencil marks only.

_________________
Quis custodiet ipsos custodes?

Normal: [D  Y-m-d,  G:i]     PM->email: [D, d M Y H:i:s]

I put it into Sudoku Solver and manually entered solved cells and eliminated candidates. Now I'm having trouble with the export function, so I'll have to fiddle around with it some more to get it to where I can post it here.


I'll look again for Naked Triplets/Quads (I *am* using pencil marks).

Other options are:

1. Screen shoot the 10 grids from Sudoku Solver ...
2. Scan or photograph your 10 paper-pages with the 10 grids ...

and post the images here.

Pencil marks are no guarantee for success!

_________________
Quis custodiet ipsos custodes?

Normal: [D  Y-m-d,  G:i]     PM->email: [D, d M Y H:i:s]

The Naked Quad is on {1589} in g2:n7 = g2:(r78c2 + r9c13) -> g2:(r7c1 + r8c3)={27}

_________________
Quis custodiet ipsos custodes?

Normal: [D  Y-m-d,  G:i]     PM->email: [D, d M Y H:i:s]

True, but they sure help! I probably wouldn't spot the triplets or quads at all without them.


That seems to be the easiest way. Here they are. Underlined candidates are locked candidates. Candidates with slanted lines under them are part of an X-wing. Circled candidates are solved cells.

Grid #1


Grid #2


Grid #3


Grid #4


Grid #5
[img]http://aam74q.bay.livefilestore.com/y1p6_uKwrTuUVBWcSLhMiaJOaHrRwVkd8pVdBU_l0Mcgl17QbbNVOTj9xijyM4LM_uifPUvY6-1svw/Clueless%204b%2005%20progress.jpg]/img]

Grid #6


Grid #7


Grid #8


Grid #9


Grid #10

Well, crud! I missed that completely! I guess I'm not very good at spotting Naked Quads yet. I would have thought, though, that I would at least spot the Hidden Pair 2,7 in that same box! I guess I've been staring at it too long.