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Set NNP Puzzle 56

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Fri Jan 23, 2009 7:38 pm    Post subject: Set NNP Puzzle 56 Reply with quote

This is not a single-stepper VH+!

Code:
 +-----------------------+
 | 6 8 . | . . 9 | . 5 3 |
 | 9 . . | . . 3 | 8 . . |
 | . . 3 | . . . | 6 . . |
 |-------+-------+-------|
 | . . . | 4 . . | 9 . . |
 | . . . | . 3 . | . 2 . |
 | 1 2 . | . . 6 | 5 . . |
 |-------+-------+-------|
 | . 6 1 | 3 . 4 | . 9 . |
 | 3 . . | . 6 . | 4 8 2 |
 | 7 . . | . . . | . 6 . |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site

===== ===== ===== ===== ===== ===== ===== ===== ===== New Ratings

Can be solved using steps from ...

Basics: Naked/Hidden Single, Naked Pair/Triple, Locked Candidate 1/2

Basics+: Naked Quad, Hidden Pair/Triple/Quad

VH: BUG+1, UR Type 1, X-Wing, XY-Wing, XYZ-Wing

VH+: 2-String Kite, Empty Rectangle, Remote Pair, Skyscraper, Colors, UR Type 2

Advanced: finned/Sashimi X-Wing, Multiple Colors, Swordfish, M-Wing, W-Wing, XY-Chain

Extreme: Jellyfish, (but mostly) Chain
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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Sun Jan 25, 2009 11:03 pm    Post subject: Reply with quote

A great VH+ puzzle!!!!

A skyscraper, a Kraken x-wing , a good fashion xy-wing and another xy-wing with a 3-cell pseudo-cell.

So when does a xy-wing with an extended pseudo-cell become a xy-chain? Here is the code prior to my last step in this puzzle.
Code:

*-----------------------------------------------------------*
 | 6     8     47    | 17    147   9     | 2     5     3     |
 | 9     1     2     | 6     5     3     | 8     4     7     |
 | 45    57    3     | 28    24    278   | 6     1     9     |
 |-------------------+-------------------+-------------------|
 | #58   3     #56   | 4     12    12    | 9     7     #68   |
 | #48   79    4679  | 589   3     578   | 1     2     468   |
 | 1     2     479   | 89    79    6     | 5     3     #48   |
 |-------------------+-------------------+-------------------|
 | 2     6     1     | 3     8     4     | 7     9     5     |
 | 3     59    59    | 17    6     17    | 4     8     2     |
 | 7     4     8     | 259   29    25    | 3     6     1     |
 *-----------------------------------------------------------*

At this point, I was looking for xy-wings and noticed the <68> & <48> cells in box6. I then started to look for a <46> cell visible to the <68> pivot and saw the 3-cell sequence in box4: <65>, <58>, and <84> which forms a <46> pseudo-cell that provides two deletions. This set of five cells is also a xy-chain. Should a 4-cell sequence still be a xy-wing , but become a xy-chain if 5 or more cells are involved? Comments Question

Ted

P.S. Also note that four of these cells form a w-wing48 with a strong link on <8> in row4.
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Mon Jan 26, 2009 12:48 am    Post subject: Reply with quote

tlanglet wrote:
So when does a xy-wing with an extended pseudo-cell become a xy-chain?

Should a 4-cell sequence still be a xy-wing , but become a xy-chain if 5 or more cells are involved?

I learned about an XY-Wing based on the pivot/vertex cell and the two wing cells. Later, I learned about an XY-Chain ... and that an XY-Wing and a 3-cell XY-Chain were different perspectives on the same three cells (and eliminations).

I presume an extended XY-Wing is just a convenient way to describe how a 4-cell (and higher) XY-Chain was located ... and a transported chain is just a way to describe how a general chain was located.
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Marty R.



Joined: 12 Feb 2006
Posts: 5063
Location: Rochester, NY, USA

PostPosted: Sun Feb 01, 2009 2:02 am    Post subject: Reply with quote

W-Wing (4Cool, Coloring (2), XY-Wing (451), then it finishes with either a W-Wing or BUG+1.
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