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A VH+

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Thu Apr 14, 2011 10:52 am    Post subject: A VH+ Reply with quote
I will not be able to post the Freep puzzle until next week. In the meantime ...
Code:
HS030411adv
+-------+-------+-------+
| 2 . . | . . 3 | . . . |
| 6 . . | 4 . . | 7 . . |
| . 5 . | 7 . . | . 8 3 |
+-------+-------+-------+
| 9 . . | . . 6 | . 5 . |
| . . . | . 9 . | . . . |
| . 8 . | 1 . . | . . 9 |
+-------+-------+-------+
| 3 1 . | . . 8 | . 2 . |
| . . 4 | . . 9 | . . 8 |
| . . . | 6 . . | . . 7 |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Fri Apr 15, 2011 12:13 am    Post subject: Reply with quote
This was a tough slog for me. The first two times I ended with an invalidity. I thought maybe with the crowded grid I had a greater chance for mechanical errors, so I did it in Draw/Play for try #3.

X-Wing (9)
XYZ-Wing (139); r8c8<>1
W-Wing (19); r2c2, r3c7<>9
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Fri Apr 15, 2011 3:29 am    Post subject: Reply with quote
Marty,

I had the same experience with the long slog.

Keith
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Fri Apr 15, 2011 6:17 pm    Post subject: Reply with quote
You can create a Kraken [c6] on <1>; but, for pizzazz ...

Code:
 networked W-Wings (with an ERI on one):

                       r2c6
                     /                      \
 (9=1)r3c3 - r3c6  =                          - (1=9)r2c8  =>  r2c23,r3c7<>9
                     \                      /
                       r9c6 - r9c78 = r89c8
 +--------------------------------------------------------------------------------+
 |  2       47      178     |  9       1568    3       |  146     146     1456    |
 |  6       3-9     138-9   |  4       1258   c125     |  7     dF19      125     |
 |  14      5      a19      |  7       126    b12      |  1246-9  8       3       |
 |--------------------------+--------------------------+--------------------------|
 |  9       347     1237    |  238     234     6       |  12348   5       124     |
 |  145     346     1236    |  238     9       2457    |  123468  13467   1246    |
 |  45      8       236     |  1       2345    2457    |  2346    3467    9       |
 |--------------------------+--------------------------+--------------------------|
 |  3       1       69      |  5       7       8       |  469     2       46      |
 |  7       26      4       |  23      123     9       |  5      E136     8       |
 |  8       29      5       |  6       1234   C124     | D139   DE139     7       |
 +--------------------------------------------------------------------------------+
 # 108 eliminations remain

I "backed out" a W-Wing, from a multi-step solution by my solver, to discover this network.
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Fri Apr 15, 2011 9:44 pm    Post subject: Reply with quote
Danny, nice one. I'm exploring more and more putting patterns in chains... How about...
Code:
(9=1)r3c3 - (1)r3c6=er(1)c6,b9[r2c6=r8c8] - (1=9)r2c8
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Sat Apr 16, 2011 1:12 am    Post subject: Reply with quote
[Withdrawn: I misunderstood.]

Last edited by daj95376 on Sat Apr 16, 2011 10:50 am; edited 1 time in total
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Sat Apr 16, 2011 2:35 am    Post subject: Reply with quote
peterj wrote:
Danny, nice one. I'm exploring more and more putting patterns in chains... How about...
Code:
(9=1)r3c3 - (1)r3c6=er(1)c6,b9[r2c6=r8c8] - (1=9)r2c8


Peter,

I just found some time to review the latest posts and noticed your input. I think it is unique and outstanding. It suggests a great understanding of the overall game status and the insight to incorporate standard patterns into an AIC to provide a clean and simple step.

I am envious........

Ted
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Sat Apr 16, 2011 7:08 am    Post subject: Reply with quote
daj95376 wrote:
Too many cells (used in my network) are missing.

Danny, it covers all the cells in your network - though granted I did not spell out the entire AIC for the er/turbot just the strong inference created.

Ted, thanks for your comment. IMHO patterns within chains is an interesting logical next step from considering almost-patterns with a single "fin" chain - which you and others have used extensivelly on this forum. I have been having a go at some of the extreme puzzles on other forums and this approach really seems powerful - and for someone brought-up on "pattern hunting" more palatable than the more austere pure-AIC approach.
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Sat Apr 16, 2011 10:53 am    Post subject: Reply with quote
peterj wrote:
Danny, it covers all the cells in your network - though granted I did not spell out the entire AIC for the er/turbot just the strong inference created.

Okay, I see what you're doing. There's an Empty Rectangle pattern and there's an Empty Rectangle technique. Since my solution used the pattern, I didn't catch that you'd used the technique.

However, I would have written it differently.

Code:
(9=1)r3c3 - (1)r3c6=er[c6b9(r2c6|r8c8)] - (1=9)r2c8

Regards, Danny
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ronk



Joined: 07 May 2006
Posts: 398
PostPosted: Sat Apr 16, 2011 2:05 pm    Post subject: Reply with quote
daj95376 wrote:
However, I would have written it differently.

Code:
 (9=1)r3c3 - (1)r3c6=er[c6b9(r2c6|r8c8)] - (1=9)r2c8

I like that too, but like this even better: (9=1)r3c3 - aer(1)c6b9:[r3c6=r2c6|r8c8] - (1=9)r2c8

The "label" for the extended/derived tri-SIS is "aer(1)c6b9:", where "aer" stands for "almost empty-rectangle (technique)." People have commented negatively about use of the colon, but it terminates a label.
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Sat Apr 16, 2011 2:48 pm    Post subject: Reply with quote
daj95376 wrote:
However, I would have written it differently.

ronk wrote:
but like this even better

Has anyone ever suggested or even tried creating a proper grammar for Eureka - using BNF or something?
Perhaps that's a foolish idealistic likes-rigour-too-much ex-computer scientist thing to ask... Rolling Eyes
"[foolish] consistency is the hobgoblin of small minds..." etc.
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