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DB Saturday Puzzle: July 14, 2007 (Corrected!!)

 
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keith



Joined: 19 Sep 2005
Posts: 3178
Location: near Detroit, Michigan, USA

PostPosted: Sat Jul 14, 2007 12:49 pm    Post subject: DB Saturday Puzzle: July 14, 2007 (Corrected!!) Reply with quote

Puzzle: DB071407 Embarassed Embarassed Embarassed Embarassed Embarassed Embarassed

Keith

Code:
Puzzle: DB071407 ******
+-------+-------+-------+
| . . . | 8 . . | 7 . . |
| 8 5 . | . . 3 | . 9 6 |
| 2 . . | . . . | . 8 . |
+-------+-------+-------+
| . . . | . . 9 | 2 . 3 |
| . . 1 | . . . | 5 . . |
| 4 . 2 | 6 . . | . . . |
+-------+-------+-------+
| . 6 . | . . . | . . 2 |
| 5 1 . | 2 . . | . 7 9 |
| . . 8 | . . 5 | . . . |
+-------+-------+-------+
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Sat Jul 14, 2007 8:32 pm    Post subject: Reply with quote

Only needed one commonly used technique.

Are you sure you didn't correct it too much?
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keith



Joined: 19 Sep 2005
Posts: 3178
Location: near Detroit, Michigan, USA

PostPosted: Sat Jul 14, 2007 8:48 pm    Post subject: Reply with quote

This is where basic methods run out of steam:
Code:
+----------------+----------------+----------------+
| 1    49   3    | 8    69   46   | 7    2    5    |
| 8    5    7    | 14   2    3    | 14   9    6    |
| 2    49   6    | 5    179  147  | 3    8    14   |
+----------------+----------------+----------------+
| 6    78   5    | 17   178  9    | 2    4    3    |
| 9    78   1    | 3    4    2    | 5    6    78   |
| 4    3    2    | 6    5    78   | 9    1    78   |
+----------------+----------------+----------------+
| 3    6    9    | 147  178  1478 | 18   5    2    |
| 5    1    4    | 2    3    68   | 68   7    9    |
| 7    2    8    | 9    16   5    | 146  3    14   |
+----------------+----------------+----------------+

I was able to solve R9C5 by multi-coloring, and then an XYZ-wing finished it off.

Keith
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jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Sat Jul 14, 2007 9:00 pm    Post subject: Reply with quote

keith wrote:


I was able to solve R9C5 by multi-coloring, and then an XYZ-wing finished it off.

Keith


A Skyscraper solves R9C5 as well, but singles is all that is required the rest of the way.
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keith



Joined: 19 Sep 2005
Posts: 3178
Location: near Detroit, Michigan, USA

PostPosted: Sat Jul 14, 2007 9:20 pm    Post subject: Reply with quote

jLo wrote:

A Skyscraper solves R9C5 as well ...

Can you point it out?

jLo wrote:

... but singles is all that is required the rest of the way.

You are correct!

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5164
Location: Rochester, NY, USA

PostPosted: Sat Jul 14, 2007 9:29 pm    Post subject: Reply with quote

From Keith's position, I also used the skyscraper to finish it off.
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jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Sat Jul 14, 2007 9:55 pm    Post subject: Reply with quote

keith wrote:

Can you point it out?



<1>s at R3C6, R3C9, R7C6, R9C9 - eliminations at R9C5 and R7C7.
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jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Sun Jul 15, 2007 12:42 am    Post subject: Reply with quote

Asellus wrote:


Are you sure you didn't correct it too much?


If you had seen the original post, you would have seen that it
was much much easier. Smile
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Earl



Joined: 30 May 2007
Posts: 546
Location: St Louis MO

PostPosted: Sun Jul 15, 2007 2:17 am    Post subject: DB July 14 Reply with quote

Keith's posted grid has <179> at R3C5.
Would it not be required to eliminate the <1> in R3C5 to have a valid skyscraper?

Perhaps I need to learn more about skyscrapers.

Earl
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jLo



Joined: 30 Apr 2007
Posts: 55

PostPosted: Sun Jul 15, 2007 4:03 am    Post subject: Re: DB July 14 Reply with quote

Earl wrote:
Keith's posted grid has <179> at R3C5.
Would it not be required to eliminate the <1> in R3C5 to have a valid skyscraper?




The skyscraper is down columns 6 and 9.

Two <1>s in column 6. Two <1>s in column 9. Row 3 is shared by both.
Eliminate the <1>s from the shared buddies of the cells that don't
share a row.

If the <1> in row three is at R3C5, then both R7C6 and R9C9 are <1>s
and the elimination is still valid.
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keith



Joined: 19 Sep 2005
Posts: 3178
Location: near Detroit, Michigan, USA

PostPosted: Sun Jul 15, 2007 4:46 am    Post subject: Reply with quote

Here is what I used:
Code:
+----------------+----------------+----------------+
| 1    49   3    | 8    69   46   | 7    2    5    |
| 8    5    7    | 14b  2    3    | 14B  9    6    |
| 2    49   6    | 5    179  147  | 3    8    14b  |
+----------------+----------------+----------------+
| 6    78   5    | 17a  178A 9    | 2    4    3    |
| 9    78   1    | 3    4    2    | 5    6    78   |
| 4    3    2    | 6    5    78   | 9    1    78   |
+----------------+----------------+----------------+
| 3    6    9    | 147  178  1478 | 18   5    2    |
| 5    1    4    | 2    3    68   | 68   7    9    |
| 7    2    8    | 9    16C  5    | 146  3    14B  |
+----------------+----------------+----------------+

In C4, a and/or b are not <1>. Following the strong links, A and/or B is <1>. Therefore C is not <1>.

This is the same logic as a skyscraper, except one "tower" is longer than one strong link.

Keith
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Earl



Joined: 30 May 2007
Posts: 546
Location: St Louis MO

PostPosted: Sun Jul 15, 2007 11:46 am    Post subject: DB July 15 Reply with quote

Is Keith's logic "multiple coloring."
.i.e. two coloring series connected?

Earl
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keith



Joined: 19 Sep 2005
Posts: 3178
Location: near Detroit, Michigan, USA

PostPosted: Sun Jul 15, 2007 9:16 pm    Post subject: Re: DB July 15 Reply with quote

Earl wrote:
Is Keith's logic "multiple coloring."
.i.e. two coloring series connected?

Earl


Yes.

Keith
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Mon Jul 16, 2007 4:11 am    Post subject: Reply with quote

It's also known as a "Color Wing" with ab as the "Bridge" between the two "Color Wraps." (It is important to note that eliminations can only occur from the polarity opposite that of the bridge; A and B in this case.)

I'm still on the lookout for a Color Wing that uses a W-Wing as the Bridge. Haven't found one yet. Maybe someone will beat me to it?
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Mon Jul 16, 2007 7:48 am    Post subject: Reply with quote

I was not familiar with "Color Wings". The 3 samples i saw here, can also be solved with "3 strong links" (like you have "2 strong links" in a skyscraper or kite).
From my experience with 2 or 3 strong links you can make more than 90% of the eliminations, that are possible with multiple coloring. I only saw a few samples, where you would need "grouped strong links".
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