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DB Saturday Puzzle: August 18, 2007

 
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keith



Joined: 19 Sep 2005
Posts: 3350
Location: near Detroit, Michigan, USA

PostPosted: Sat Aug 18, 2007 11:54 am    Post subject: DB Saturday Puzzle: August 18, 2007 Reply with quote

Code:
Puzzle: DB081807  ******
+-------+-------+-------+
| . . 3 | 4 . . | . 6 . |
| . . . | . 8 . | . . 7 |
| 2 5 . | . . 3 | . 4 . |
+-------+-------+-------+
| 8 . 6 | . . . | . . 4 |
| . 3 . | 2 . 4 | . 8 . |
| 4 . . | . . . | 3 . 9 |
+-------+-------+-------+
| . 7 . | 3 . . | . 1 2 |
| 6 . . | . 5 . | . . . |
| . 9 . | . . 1 | 6 . . |
+-------+-------+-------+
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TKiel



Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI

PostPosted: Sat Aug 18, 2007 1:27 pm    Post subject: Reply with quote

Nice puzzle to practice looking for XY-wings and W-wings; of course your eyes may go crossed before you find something that helps.
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Earl



Joined: 30 May 2007
Posts: 642
Location: Victoria, KS

PostPosted: Sat Aug 18, 2007 2:18 pm    Post subject: DB Aug 18 Reply with quote

I had to use a four step xy-chain from R4C4 to R3C7 to eliminate the 9 from R3C4, which opened the puzzle.

Anyone find a cleaner way?

Earl
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Steve R



Joined: 24 Oct 2005
Posts: 289
Location: Birmingham, England

PostPosted: Sat Aug 18, 2007 3:03 pm    Post subject: Reply with quote

A single w-wing will do, I think

Steve
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Marty R.



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

PostPosted: Sat Aug 18, 2007 4:39 pm    Post subject: Reply with quote

I couldn't find any XY-Wings or W-Wings. But one XY-Chain (or maybe it wasn't an XY-Chain) did the trick.

The definition of an XY-Chain is that it's a chain of bivalue cells. My chain had one trivalue cell. Do you folks adhere strictly to the definition? If so, what would you call my solution?

Quote:
Anyone find a cleaner way?


Tough one to answer Earl, without knowing your standards of cleanliness. Wink
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keith



Joined: 19 Sep 2005
Posts: 3350
Location: near Detroit, Michigan, USA

PostPosted: Sat Aug 18, 2007 6:13 pm    Post subject: Reply with quote

Basic moves get you to here:
Code:
+-------------+-------------+-------------+
| 179 8   3   | 4   2   79  | 59  6   15  |
| 19  6   4   | 159 8   59  | 2   3   7   |
| 2   5   79  | 169 167 3   | 89  4   18  |
+-------------+-------------+-------------+
| 8   12  6   | 159 3   579 | 157 257 4   |
| 79  3   579 | 2   17  4   | 157 8   6   |
| 4   12  57  | 156 167 8   | 3   257 9   |
+-------------+-------------+-------------+
| 5   7   8   | 3   9   6   | 4   1   2   |
| 6   4   1   | 78  5   2   | 78  9   3   |
| 3   9   2   | 78  4   1   | 6   57  58  |
+-------------+-------------+-------------+

There is a skyscraper on <7> in C16 which solves R5C5 as <1>. You can then proceed with an X-wing and two XY-wings.

Or, there is a W-wing <79> in B12 with the strong link on <9> in C7. It takes out <7> in R1C1 and R3C5 and solves the puzzle.

Keith
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Hasel



Joined: 23 Aug 2007
Posts: 4

PostPosted: Fri Aug 24, 2007 12:38 pm    Post subject: Reply with quote

I am confused...........






Hasel
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Marty R.



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

PostPosted: Fri Aug 24, 2007 3:52 pm    Post subject: Reply with quote

Hasel wrote:
I am confused...........


Over what in particular? Question
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TKiel



Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI

PostPosted: Fri Aug 24, 2007 3:58 pm    Post subject: Reply with quote

That no one is visiting his site?
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Mogulmeister



Joined: 03 May 2007
Posts: 703

PostPosted: Fri Aug 24, 2007 4:05 pm    Post subject: Reply with quote

Exactly Tracy !
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Myth Jellies



Joined: 27 Jun 2006
Posts: 64

PostPosted: Thu Aug 30, 2007 11:09 pm    Post subject: Reply with quote

After the skyscraper or sashimi x-wing in sevens sets r5c5 = 1 and then a few others as well, then there is also a 59 UR in r24c46 with three strong links that eliminates the 5 in r4c6 and solves the puzzle.
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