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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Jul 14, 2007 12:49 pm Post subject: DB Saturday Puzzle: July 14, 2007 (Corrected!!) |
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Puzzle: DB071407
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
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Posted: Sat Jul 14, 2007 8:32 pm Post subject: |
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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: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Jul 14, 2007 8:48 pm Post subject: |
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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
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Posted: Sat Jul 14, 2007 9:00 pm Post subject: |
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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: 3355 Location: near Detroit, Michigan, USA
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Posted: Sat Jul 14, 2007 9:20 pm Post subject: |
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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: 5770 Location: Rochester, NY, USA
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Posted: Sat Jul 14, 2007 9:29 pm Post subject: |
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From Keith's position, I also used the skyscraper to finish it off. |
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jLo
Joined: 30 Apr 2007 Posts: 55
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Posted: Sat Jul 14, 2007 9:55 pm Post subject: |
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keith wrote: |
Can you point it out?
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<1>s at R3C6, R3C9, R7C6, R9C9 - eliminations at R9C5 and R7C7. |
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jLo
Joined: 30 Apr 2007 Posts: 55
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Posted: Sun Jul 15, 2007 12:42 am Post subject: |
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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. |
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Earl
Joined: 30 May 2007 Posts: 677 Location: Victoria, KS
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Posted: Sun Jul 15, 2007 2:17 am Post subject: DB July 14 |
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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
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Posted: Sun Jul 15, 2007 4:03 am Post subject: Re: DB July 14 |
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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?
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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: 3355 Location: near Detroit, Michigan, USA
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Posted: Sun Jul 15, 2007 4:46 am Post subject: |
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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: 677 Location: Victoria, KS
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Posted: Sun Jul 15, 2007 11:46 am Post subject: DB July 15 |
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Is Keith's logic "multiple coloring."
.i.e. two coloring series connected?
Earl |
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keith
Joined: 19 Sep 2005 Posts: 3355 Location: near Detroit, Michigan, USA
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Posted: Sun Jul 15, 2007 9:16 pm Post subject: Re: DB July 15 |
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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
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Posted: Mon Jul 16, 2007 4:11 am Post subject: |
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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
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Posted: Mon Jul 16, 2007 7:48 am Post subject: |
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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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