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Set NNP Puzzle 7

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Thu Jan 22, 2009 5:56 am    Post subject: Set NNP Puzzle 7 Reply with quote
Code:
 +-----------------------+
 | . . . | 2 . . | . . 6 |
 | . 2 . | . . . | 5 . . |
 | . . 8 | 3 . 5 | . . . |
 |-------+-------+-------|
 | 4 . 2 | 8 . 9 | . 6 5 |
 | . . . | . 1 . | . 4 2 |
 | . . 5 | 4 . . | 3 . 8 |
 |-------+-------+-------|
 | . 3 . | . . 7 | 6 . . |
 | . . . | 6 5 . | . . . |
 | 2 . . | 9 8 3 | . . 4 |
 +-----------------------+

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: 2468
Location: Northern California Foothills
PostPosted: Thu Jan 22, 2009 7:53 pm    Post subject: Reply with quote
After basics, I was stuck but started looking for xy-chains instead of giving up as I usually do. I finally found a forcing chain!!!
Code:

 *-----------------------------------------------------------*
 | 1357  457   137   | 2     9    a18    |i48    378   6     |
 | 1369  2     1369  | 7     4    b18    | 5     389  c13    |
 | 179   479   8     | 3     6     5     |h24    279   17    |
 |-------------------+-------------------+-------------------|
 | 4     1     2     | 8     3     9     | 7     6     5     |
 | 378   78    37    | 5     1     6     | 9     4     2     |
 | 69    69    5     | 4     7     2     | 3     1     8     |
 |-------------------+-------------------+-------------------|
 | 58    3     4     | 1     2     7     | 6    f58    9     |
 | 1789  789   179   | 6     5     4     |g28    2378 d37    |
 | 2     567   67    | 9     8     3     | 1    e57    4     |
 *-----------------------------------------------------------*

If cell "a" (at r1c6) = <8>, then the chain from "a" => "i" gives i" "(at r1c7) = <8> which is a conflict. Thus r1c6=1. A xy-wing578 and a Type 1 UR37 finish off the puzzle.

Ted Very Happy
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
PostPosted: Fri Jan 23, 2009 1:12 am    Post subject: Reply with quote
I like this xy-chain better and it has the same result. Smile

Code:
 *-----------------------------------------------------------*
 | 1357  457   137   | 2     9     18    | 48    378   6     |
 | 1369  2     1369  | 7     4    a18    | 5     39-8 b13    |
 | 179   479   8     | 3     6     5     | 24    279   17    |
 |-------------------+-------------------+-------------------|
 | 4     1     2     | 8     3     9     | 7     6     5     |
 | 378   78    37    | 5     1     6     | 9     4     2     |
 | 69    69    5     | 4     7     2     | 3     1     8     |
 |-------------------+-------------------+-------------------|
 | 58    3     4     | 1     2     7     | 6    e58    9     |
 | 1789  789   179   | 6     5     4     | 28    2378 c37    |
 | 2     567   67    | 9     8     3     | 1    d57    4     |
 *-----------------------------------------------------------*
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Fri Jan 23, 2009 1:22 am    Post subject: Reply with quote
wapati wrote:
I like this xy-chain better and it has the same result. Smile

Code:
 *-----------------------------------------------------------*
 | 1357  457   137   | 2     9     18    | 48    378   6     |
 | 1369  2     1369  | 7     4    a18    | 5     39-8 b13    |
 | 179   479   8     | 3     6     5     | 24    279   17    |
 |-------------------+-------------------+-------------------|
 | 4     1     2     | 8     3     9     | 7     6     5     |
 | 378   78    37    | 5     1     6     | 9     4     2     |
 | 69    69    5     | 4     7     2     | 3     1     8     |
 |-------------------+-------------------+-------------------|
 | 58    3     4     | 1     2     7     | 6    e58    9     |
 | 1789  789   179   | 6     5     4     | 28    2378 c37    |
 | 2     567   67    | 9     8     3     | 1    d57    4     |
 *-----------------------------------------------------------*


Yes, I also think it is a simpler chain and therefore better. However, my knowledge of Suduko, particularly dealing with chains, is still very limited, and any chain that works is great. I only find chains by brute force, not by enlightened insight. Hopefully I will gain insight in the future and address more constructive chains. At this stage, any solution is a victory!

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Fri Jan 23, 2009 1:51 am    Post subject: Reply with quote
tlanglet wrote:
However, my knowledge of Suduko, particularly dealing with chains, is still very limited, and any chain that works is great. I only find chains by brute force, not by enlightened insight. Hopefully I will gain insight in the future and address more constructive chains. At this stage, any solution is a victory!

Anyone who finds any chain that works has my admiration!!! This includes extended and/or transported. Since I tend to think in terms of forcing chain patterns, they're what I spot first as well.

I have a number of puzzles waiting to be posted that have an XY-Chain, M-Wing, and/or W-Wing that will crack them open. None will be in the posts I'm currently adding! Smile
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