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VH: Set B Puzzle 1

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sat Nov 22, 2008 1:26 am    Post subject: VH: Set B Puzzle 1 Reply with quote

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

Play this puzzle online at the Daily Sudoku site
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sat Nov 22, 2008 5:06 am    Post subject: Reply with quote

More wings than a Buffalo chicken!

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Sat Nov 22, 2008 5:17 am    Post subject: Reply with quote

keith wrote:
More wings than a Buffalo chicken!

But just one was needed, which was the first one I saw.

Quote:
W-Wing on 26
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Sat Nov 22, 2008 11:57 am    Post subject: Reply with quote

A fun puzzle.

Quick during basics,
surprisingly many decoys (wings and transportations that looked like they might solve the puzzle but then didn't)
and an "elegant" (right, dan/arkietech ?) solution (which I missed first time around, cause I stupidly forgot to cross out a candidate 5 in the r8c1 pencil marks, which prevented me from finding the w-wing...)

Thanks Danny, keep those puzzles coming!
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Sat Nov 22, 2008 12:27 pm    Post subject: Reply with quote

nataraj wrote:
surprisingly many decoys (wings and transportations that looked like they might solve the puzzle but then didn't)
and an "elegant" (right, dan/arkietech ?) solution (which I missed first time around, cause I stupidly forgot to cross out a candidate 5 in the r8c1 pencil marks, which prevented me from finding the w-wing...)

Right on Very Happy A gem that needs to be looked at for a while.
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Sat Nov 22, 2008 3:33 pm    Post subject: Reply with quote

I'm not a wing nut. I have trouble finding them - even using recommended techniques. So I gave up, went back the Forum, and saw it was wingable. I certainly didn't finish with one wing as did Marty - it took me about 7 or 8 incl. an x-wing and xyz wing.
This one should be required reading for a wing licence.
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Sat Nov 22, 2008 6:47 pm    Post subject: Reply with quote

After some study this is the best I could do
Code:
 *-----------------------------------------------------------*
 | 7     6     9     | 3     8     1     | 4     5     2     |
 | 1     5     4     | 9     7     2     | 38    38    6     |
 | 8     3     2     | 4     5     6     | 9     7     1     |
 |-------------------+-------------------+-------------------|
 | 9     4    C36    | 1    B23    8     | 5     236   7     |
 | 35-6  7     1     |A26    9     45    | 36    2346  8     |
 | 356   2     8     | 67    34    457   | 1     346   9     |
 |-------------------+-------------------+-------------------|
 | 236   18    36    | 5     12    9     | 7     68    4     |
 | 26    18    5     | 27    124   47    | 68    9     3     |
 | 4     9     7     | 8     6     3     | 2     1     5     |
 *-----------------------------------------------------------*
xy-wing starts it
 *-----------------------------------------------------------*
 | 7     6     9     | 3     8     1     | 4     5     2     |
 | 1     5     4     | 9     7     2     |G38    38    6     |
 | 8     3     2     | 4     5     6     | 9     7     1     |
 |-------------------+-------------------+-------------------|
 | 9     4     36    | 1     23    8     | 5     236   7     |
 |A35    7     1     | 26    9    B45    | 6-3   2346  8     |
 | 356   2     8     | 67    34    457   | 1     346   9     |
 |-------------------+-------------------+-------------------|
 | 236   18    36    | 5     12    9     | 7     68    4     |
 |E26    18    5     |D27    124  C47    |F68    9     3     |
 | 4     9     7     | 8     6     3     | 2     1     5     |
 *-----------------------------------------------------------*
xy-chain finishes it off


Edit: added omitted cell in chain


Last edited by arkietech on Sat Nov 22, 2008 11:53 pm; edited 1 time in total
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Sat Nov 22, 2008 6:58 pm    Post subject: Reply with quote

dan, the w-wing Marty mentioned:

(2)r8c1=r5c4 (via SL (6) in col 7)

does the job in one step.
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Sat Nov 22, 2008 7:22 pm    Post subject: Reply with quote

nataraj wrote:
dan, the w-wing Marty mentioned:

(2)r8c1=r5c4 (via SL (6) in col 7)

does the job in one step.
Elegent Very Happy
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sat Nov 22, 2008 10:08 pm    Post subject: Reply with quote

cgordon wrote:
I'm not a wing nut. I have trouble finding them - even using recommended techniques. So I gave up, went back the Forum, and saw it was wingable. I certainly didn't finish with one wing as did Marty - it took me about 7 or 8 incl. an x-wing and xyz wing.
This one should be required reading for a wing license.

I am a terrible manual solver ... unless I have a solver to help me by highlighting candidates and pairs. Then, I jump up to mediocre (sic?) status.

I agree that this puzzle can be very taxing. There are three XY-Wings present after basics. Together, they crack the puzzle. However, performing them individually leads to additional XY-Wings being exposed, along with eliminations from other techniques, that might distract you.

Code:
 XY-Wing  [r5c4]/[r4c5]+[r5c7]   <> 3    [r4c8]
 XY-Wing  [r4c5]/[r4c3]+[r5c4]   <> 6    [r5c1]
 XY-Wing  [r8c4]/[r6c4]+[r8c1]   <> 6    [r6c1]
 *-----------------------------------------------------------*
 | 7     6     9     | 3     8     1     | 4     5     2     |
 | 1     5     4     | 9     7     2     | 38    38    6     |
 | 8     3     2     | 4     5     6     | 9     7     1     |
 |-------------------+-------------------+-------------------|
 | 9     4     36    | 1     23    8     | 5     236   7     |
 | 356   7     1     | 26    9     45    | 36    2346  8     |
 | 356   2     8     | 67    34    457   | 1     346   9     |
 |-------------------+-------------------+-------------------|
 | 236   18    36    | 5     12    9     | 7     68    4     |
 | 26    18    5     | 27    124   47    | 68    9     3     |
 | 4     9     7     | 8     6     3     | 2     1     5     |
 *-----------------------------------------------------------*


Dan (arkietech): You forgot to include [r8c1] in your XY-Chain -- what fun you must have had running it down!
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sat Nov 22, 2008 11:24 pm    Post subject: Reply with quote

Yes, this was a fun puzzle that had lots of wings. I initially solved it using only xy-wings most including the digit <2>, but I then worked it out using other techniques.

Ted
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Sat Nov 22, 2008 11:57 pm    Post subject: Reply with quote

daj95376 wrote:
[Dan (arkietech): You forgot to include [r8c1] in your XY-Chain -- what fun you must have had running it down!

Oops! Embarassed Thanks I fixed it in the original post.
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