dailysudoku.com Forum Index dailysudoku.com
Discussion of Daily Sudoku puzzles
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

December 23 VH

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles
View previous topic :: View next topic  
Author Message
Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Sun Dec 23, 2012 4:48 am    Post subject: December 23 VH Reply with quote
Code:

+---------+--------------+------------+
| 9 34 7  | 14  8    13  | 5  6    2  |
| 5 8  6  | 2   379  379 | 39 1    4  |
| 1 34 2  | 469 369  5   | 7  39   8  |
+---------+--------------+------------+
| 3 27 19 | 579 2579 6   | 8  4    15 |
| 4 27 8  | 57  1    37  | 6  235  9  |
| 6 5  19 | 8   239  4   | 13 23   7  |
+---------+--------------+------------+
| 2 6  4  | 3   579  789 | 19 5789 15 |
| 8 1  5  | 679 679  2   | 4  79   3  |
| 7 9  3  | 15  4    18  | 2  58   6  |
+---------+--------------+------------+

I needed three moves, but I'm not confident that it couldn't be done in less.

X-Wing on 9 in c67 and X-Wing on 5 in c59. That gets me here where an XY-Wing on 78-5 pivoted in r7c8 finishes it off.


Play this puzzle online at the Daily Sudoku site
Code:

+---------+--------------+-----------+
| 9 34 7  | 14  8    13  | 5  6   2  |
| 5 8  6  | 2   37   379 | 39 1   4  |
| 1 34 2  | 469 369  5   | 7  39  8  |
+---------+--------------+-----------+
| 3 27 19 | 79  2579 6   | 8  4   15 |
| 4 27 8  | 57  1    37  | 6  235 9  |
| 6 5  19 | 8   239  4   | 13 23  7  |
+---------+--------------+-----------+
| 2 6  4  | 3   57   789 | 19 78  15 |
| 8 1  5  | 679 679  2   | 4  79  3  |
| 7 9  3  | 15  4    18  | 2  58  6  |
+---------+--------------+-----------+

Play this puzzle online at the Daily Sudoku site
Back to top
View user's profile Send private message
arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
PostPosted: Sun Dec 23, 2012 8:47 am    Post subject: Reply with quote
Code:
 *-----------------------------------------------------------*
 | 9     34    7     | 14    8     13    | 5     6     2     |
 | 5     8     6     | 2     379   379   | 39    1     4     |
 | 1     34    2     | 469   369   5     | 7     39    8     |
 |-------------------+-------------------+-------------------|
 | 3    d27    19    | 579  e279-5 6     | 8     4    a15    |
 | 4    c27    8     | 57    1     37    | 6    b235   9     |
 | 6     5     19    | 8     239   4     | 13    23    7     |
 |-------------------+-------------------+-------------------|
 | 2     6     4     | 3     579   789   | 19    5789  15    |
 | 8     1     5     | 679   679   2     | 4     79    3     |
 | 7     9     3     | 15    4     18    | 2     58    6     |
 *-----------------------------------------------------------*
L-wing
5r4c9=(5-2)r5c8=r5c2-r4c2=2r4c5 => -5r4c5; stte
Back to top
View user's profile Send private message
George Woods



Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
PostPosted: Sun Dec 23, 2012 10:17 am    Post subject: Has this variation of an xy wing got a name? Reply with quote
After the x wing in 5 we can 'pivot' r4c4 if it is 9 then r4c3 denies a 1 to r4c9 which becomes 5. aliter if r4c4 is 7 then r5c4 is 5 which forces r4c9 to be 5

so r4c9 =5

but it is not an xy wing

I came to this by observing that r3c23 must contain a 1 or a2 (ellse r4c4 cannot be satisfied) this leads to a similar artgument to that given above. So it was frustrating to find that I couldn't force the argument into any known (by me) formal structure
Back to top
View user's profile Send private message
JC Van Hay



Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium
PostPosted: Sun Dec 23, 2012 11:55 am    Post subject: Re: Has this variation of an xy wing got a name? Reply with quote
George Woods wrote:
...So it was frustrating to find that I couldn't force the argument into any known (by me) formal structure

Code:
+-------------+-------------------+----------------+
| 9  34  7    | 14     8      13  | 5   6     2    |
| 5  8   6    | 2      379    379 | 39  1     4    |
| 1  34  2    | 469    369    5   | 7   39    8    |
+-------------+-------------------+----------------+
| 3  27  (19) | (579)  279-5  6   | 8   4     (15) |
| 4  27  8    | (57)   1      37  | 6   235   9    |
| 6  5   19   | 8      239    4   | 13  23    7    |
+-------------+-------------------+----------------+
| 2  6   4    | 3      579    789 | 19  5789  15   |
| 8  1   5    | 679    679    2   | 4   79    3    |
| 7  9   3    | 15     4      18  | 2   58    6    |
+-------------+-------------------+----------------+
(5=7)r5c4-(7=159)r4c349 :=> -5r4c5

Extended WXYZ-Wing Type 1 or ALS X-Z Rule : W=7(restricted common), X=1, Y=9, Z=5 (common); WXYZ as r4c4, XYZ and XYZ as r4c39, WZ as r5c4 --> (Z=W)-(W=XYZ) :=> -Z.
XY Chain if 5r4c4 is already eliminated. In this case, -5r4c5 and -5r5c8.

In both case, the XWing on 5 is solved.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Daily Sudoku puzzles All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group