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Daily Sudoku Competition for Mar 6, 2011

 
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Mon Mar 07, 2011 7:45 am    Post subject: Daily Sudoku Competition for Mar 6, 2011 Reply with quote

009600014003080200006001000100700006000010000500002007000900300000050000940003500

Code:

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

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Asellus



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

PostPosted: Mon Mar 07, 2011 10:45 pm    Post subject: Reply with quote

I found 3 steps:
Quote:
[1] 578XYW; r4c7<>8
[2] 128DP r89c349; r8c9=9
[3] 18URr89c34[(8)r4c3=(8)r56c4]; r4c6<>8
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tlanglet



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

PostPosted: Tue Mar 08, 2011 2:30 pm    Post subject: Reply with quote

I used 5 steps........

Quote:
xy-wing (57-8) vertex (57)r1c6; r4c7<>8
ANP(58=2)r13c2-(5)r1c2=r1c6-(5=8)r4c6; r4c2<>8
(2=8)r1c1-(8=5)r3c2-r3c4=r1c6-(5=8)r4c6-(8=2)r4c3; r5c1<>2
xy-wing (-238)vertex (38)r5c1; r1c2<>2
ANP(48=7)r78c6-(4)r8c6=r8c8-(4=8)r7c8-r6c8=(8)r6c4; r4c6<>8

Ted
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tlanglet



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

PostPosted: Tue Mar 08, 2011 2:51 pm    Post subject: Reply with quote

Asellus,

I also looked at the ADP(128) in r89c349. I considered it as 6-cells either (18)r89c3|(12)r89c4|(28)r89c9 or (12)r89c3|(18)r89c4|(28)r89c9 using both internal and external inferences, but was not able to make any conclusions.

I also wondered if the pattern was like a Type 1 MUG which would directly set r8c9=9, but I am still unsure of the rules that define a MUG.

Would you please elaborate on your logic?

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Tue Mar 08, 2011 2:54 pm    Post subject: Reply with quote

I kept half-expecting wapati to come along and jump on this puzzle. Since he's off somewhere else, I'll provide a solution for him.

Code:
 after basics, XY-Wing, and more basics:
 +--------------------------------------------------------------+
 | *28   *258   9     |  6     3     57    |  78    1     4     |
 |  7     1     3     |  4     8     9     |  2     6     5     |
 |  4     58    6     |  25    27    1     |  78    39    39    |
 |--------------------+--------------------+--------------------|
 |  1    *238  #28    |  7     4     5-8   |  9     2358  6     |
 | *238   9     7     |  358   1     6     |  4     2358  238   |
 |  5     6     4     | #38    9     2     |  1    *38    7     |
 |--------------------+--------------------+--------------------|
 |  6    *278   5     |  9     27   *478   |  3    *248   1     |
 |  238   2378  128   |  128   5     478   |  6     2489  289   |
 |  9     4     128   |  128   6     3     |  5     7     28    |
 +--------------------------------------------------------------+
 # 57 eliminations remain

 Sashimi Franken Jellyfish               <> 8    r4c6
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Asellus



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

PostPosted: Tue Mar 08, 2011 4:55 pm    Post subject: Reply with quote

Ted wrote:
I also wondered if the pattern was like a Type 1 MUG which would directly set r8c9=9, but I am still unsure of the rules that define a MUG.

Would you please elaborate on your logic?

Yes, it is a "Type 1" MUG. That <9> is the only digit that avoids the MUG deadly pattern. As for recognizing such patterns, I suggest reading Myth Jellies's post here. Some of the possible MUGs discussed there are beyond my ability to spot readily. However, the one here is easy. Start with the "3-digit 2-row 3-column 3-box" permeable MUG. Then, as Myth Jellies says, "any deadly pattern that you come up with when reducing a deadly pattern also qualifies as a deadly pattern." Here, the pattern is reduced by a <1> in b9. The pattern could be reduced by any or all of <1>, <2> and <8> distributed amongst the 3 boxes and it would still be deadly.
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Tue Mar 08, 2011 5:17 pm    Post subject: Reply with quote

Danny, great fish! There is no-way I would find something like that - unless perhaps it was also a grouped x-chain or stumbled on it when on one of my broken-wing excursions. I still find even a Swordfish something of a struggle Rolling Eyes
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Tue Mar 08, 2011 7:04 pm    Post subject: Reply with quote

peterj wrote:
Danny, great fish!

Yes. I wish that I could take credit for finding it w/o my solver. That's why I waited 1.5 days before posting the solution. I believe wapati loves to solve complicated fish patterns manually ... and I wanted to give him time to take credit for finding it.

Regards, Danny
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Marty R.



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

PostPosted: Fri Mar 11, 2011 5:35 am    Post subject: Reply with quote

W-Wing (58) plus transport
Potential 18 DP in boxes 78, a 2 is needed to kill it, common outcome solves box 2
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