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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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 Posted: Sat Feb 16, 2008 4:17 am Post subject: Feb 16, 2008 VH |
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| Code: | |---c1--|---c2--|---c3--||---c4--|---c5--|---c6--||---c7--|---c8--|---c9--
-----------------------------------------------------------------------------
r1 | 7 | 1 | 9 || 46 | 5 | 346 || 8 | 2 | 346
---+-------+-------+-------||-------+-------+-------||-------+-------+-------
r2 | 8 | 2 | 34 || 1 | 346 | 9 || 56 | 345 | 7
---+-------+-------+-------||-------+-------+-------||-------+-------+-------
r3 | 6 | 5 | 34 || 2 | 7 | 8 || 1 | 9 | 34
===========================||=======================||=======================
r4 | 9 | 4 | 27 || 78 | 28 | 1 || 3 | 6 | 5
---+-------+-------+-------||-------+-------+-------||-------+-------+-------
r5 | 1 | 8 | 67 || 3 | 46 | 5 || 9 | 47 | 2
---+-------+-------+-------||-------+-------+-------||-------+-------+-------
r6 | 5 | 3 | 267 || 9 | 246 | 467 || 47 | 1 | 8
===========================||=======================||=======================
r7 | 2 | 6 | 5 || 478 | 1 | 347 || 47 | 3478 | 9
---+-------+-------+-------||-------+-------+-------||-------+-------+-------
r8 | 4 | 9 | 1 || 578 | 38 | 2 || 56 | 3578 | 36
---+-------+-------+-------||-------+-------+-------||-------+-------+-------
r9 | 3 | 7 | 8 || 456 | 9 | 46 || 2 | 45 | 1
............................................................................. |
I can see a difference in approaches already with this one.
the ones that favor wings will go with an x-wing on 7
xyz-wing on r6c5 {2,4,6}
the ones that color first will fall in love with the number 3, it makes two eliminations and solves the puzzle. |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Sat Feb 16, 2008 9:18 am Post subject: |
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A Finned x-wing takes out <3> in R8C9, either the fin(F) is true or the x-wing@, in both cases they eliminate <3> in R8C9.
| Code: | +--------------------------+--------------------------+--------------------------+
| 7 1 9 | 46 5 346 | 8 2 346 |
| 8 2 34 | 1 @ 346 9 | 56 @ 35 7 |
| 6 5 34 | 2 7 8 | 1 9 34 |
+--------------------------+--------------------------+--------------------------+
| 9 4 27 | 78 28 1 | 3 6 5 |
| 1 8 67 | 3 46 5 | 9 47 2 |
| 5 3 267 | 9 246 467 | 47 1 8 |
+--------------------------+--------------------------+--------------------------+
| 2 6 5 | 478 1 347 | 47 F 3478 9 |
| 4 9 1 | 578 @ 38 2 | 56 @ 3578 -[3]6 |
| 3 7 8 | 456 9 46 | 2 45 1 |
+--------------------------+--------------------------+--------------------------+ |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sat Feb 16, 2008 9:34 am Post subject: |
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| Code: | +--------------------------+--------------------------+--------------------------+
| 7 1 9 | 46 5 R346 | 8 2 G346 |
| 8 2 34 | 1 G346 9 | 56 -[3]5 7 |
| 6 5 34 | 2 7 8 | 1 9 34 |
+--------------------------+--------------------------+--------------------------+
| 9 4 27 | 78 28 1 | 3 6 5 |
| 1 8 67 | 3 46 5 | 9 47 2 |
| 5 3 267 | 9 246 467 | 47 1 8 |
+--------------------------+--------------------------+--------------------------+
| 2 6 5 | 478 1 G347 | 47 R3478 9 |
| 4 9 1 | 578 R38 2 | 56 3578 -[3]6 |
| 3 7 8 | 456 9 46 | 2 45 1 |
+--------------------------+--------------------------+--------------------------+ |
this is Johan's grid with the coloring on 3 in it.
it does the same thing that the finned creature did and it eliminates the 3 in r2c8 and r8c9 because they both see a red and a green 3 |
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andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
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| Posted: Sat Feb 16, 2008 10:38 am Post subject: |
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A very interesting one, but I'm glad it was a Saturday puzzle, as it kept me going for quite a while!
John |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Sat Feb 16, 2008 11:08 am Post subject: |
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That coloring on <3> (ignoring c5, which doesn't really add anything) is also called a Skyscraper, it so happens.
The Finned X-Wing has the same effect due to the resulting locked candidates. (r28 is also a Finned X-Wing with the same overall result.)
Or, if you prefer, the b9/r2 ER eliminates <3> in r8c5 as yet another path to the same place.
So, at least 5 ways to see it. |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Sat Feb 16, 2008 11:50 am Post subject: |
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For me, it was the skyscraper (the one that takes out 3 in r2c8).
Very straightforward, this one. There were so few multi-value (more than 2) cells left after basics that I spent most of the time trying to find a xy(z) wing (and failed to see the one that was present !!!) and only then turned to the coloring approach.
Guess there are more chains than wings in my nature... |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Feb 16, 2008 3:56 pm Post subject: |
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| I couldn't see a solution using the built-in techniques needed to solve these. I did have an X-Wing and XY-Wing, but it was an ER on 3 that broke it open. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Feb 16, 2008 4:35 pm Post subject: |
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| Marty R. wrote: | | I couldn't see a solution using the built-in techniques needed to solve these. I did have an X-Wing and XY-Wing, but it was an ER on 3 that broke it open. |
This, after basics:
| Code: | +----------------+----------------+----------------+
| 7 1 9 | 46 5 346 | 8 2 346 |
| 8 2 34 | 1 346 9 | 56 35 7 |
| 6 5 34 | 2 7 8 | 1 9 34 |
+----------------+----------------+----------------+
| 9 4 27 | 78 28 1 | 3 6 5 |
| 1 8 67 | 3 46 5 | 9 47 2 |
| 5 3 267 | 9 246 467 | 47 1 8 |
+----------------+----------------+----------------+
| 2 6 5 | 478 1 347 | 47 3478 9 |
| 4 9 1 | 578 38 2 | 56 3578 36 |
| 3 7 8 | 456 9 46 | 2 45 1 |
+----------------+----------------+----------------+
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There is an XYZ-wing <46> that takes out <4> in R6C5.
An X-wing in R67C67 that talkes out <7> in three cells in R67.
Then, some cleaning up lets you solve R2C7, and the puzzle is done.
Not quite how I did it. After the above wings, there turns out to be an X-wing that takes out <6> in R1C9, which also solves it.
Keith |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sun Feb 17, 2008 9:58 am Post subject: |
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I know this really isn't the place to discuss this, but if you have been watching the Blu-Ray vs HD DVD war... Blu-Ray got a big boost this past week when toshiba won't be making any devices that read HD DVDs, and wal-mart is not selling HD DVDs, and Netflix is not going to offer HD-DVDs. its all Blu-Ray for those companies.
any picks for the Daytona? |
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sdq_pete
Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL
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| Posted: Sun Feb 17, 2008 12:02 pm Post subject: |
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Summarising the X moves, I had: | Code: | XYZ 467 R6C6
X 7 C67
XY 478 R4C4 |
A UR also arose in that little 47 square (R67 C67) though I didn't need it.
Strangely, recognising X-wings is my Achilles heel, even though from a logical point of view it is the simplest of the "advanced" techniques. In this case, I recognised the square of 4's as potential X-wing but for some reason missed the 7's... Weird! Just thought I'd get that off my chest.
Peter |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Mon Feb 18, 2008 8:52 pm Post subject: |
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| Quote: | | Strangely, recognising X-wings is my Achilles heel, even though from a logical point of view it is the simplest of the "advanced" techniques |
hi Peter,
I'd also like to throw the type 1 UR in there as the easiest to see visually. and probably just as easy to understand logically as the x-wing. for my two cents. |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Wed Feb 20, 2008 9:43 pm Post subject: |
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| sdq_pete wrote: | A UR also arose in that little 47 square (R67 C67) though I didn't need it.
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Peter, I just don't get it (and bear in mind MY Achilles' heel is URs) - how can a rectangle covering four boxes ever be part of a DP? Your square has one foot in each of the four boxes. How does that work?
| storm_norm wrote: | | and probably just as easy to understand logically as the x-wing. for my two cents |
Sorry, Norm, I don't (understand it as easily). I would appreciate it if you'd explain. Or maybe you guys are referring to something different. Please - help me. I seriously do not know what you are talking about. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Wed Feb 20, 2008 11:32 pm Post subject: |
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nataraj,
sorry, I didn't know the UR was happening over 4 boxes. if it is then its not a UR.
I was merely stating that the type 1 UR is visually easy to see.
and you are right. a UR can only happen in 2 boxes. |
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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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| Posted: Thu Feb 21, 2008 6:21 am Post subject: |
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Thanks, Norm! While I do agree that possible URs attract attention much more than possible x-wings (I mean, they are practically jumping out of the grid and wave a flag saying "here I am, do something!"  ), I find it much easier to grasp and immediately apply x-wing logic than the logic behind UR types above 1 or non-rectangular DPs. I continue to be amazed at what ravel and others can do with those patterns, but when I encounter them myself it takes me forever to develop the reasoning and convince myself that, yes, in this case x can be removed because of ... [insert whatever type logic applies]
keith's guide helps a lot but I guess it takes a lot of practice to really feel comfortable with those URs.  |
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