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 

Mon Feb 14th VH

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



Joined: 05 Apr 2010
Posts: 422
Location: Birmingham UK

PostPosted: Mon Feb 14, 2011 11:17 am    Post subject: Mon Feb 14th VH Reply with quote

I'm not so hot on these- was this a more complicated VH than usual? After the
obvious (and unnecessary?) 25 UR I got a colouring on a chain of 6's removing
6 from C1 and then a 246 XY wing pivoting on C8. Was there an easier way?

By the way- where is everyone? Very late for a first post.....


After basics
Code:

+----------------+----------+--------------+
| 69    1    3   | 8 4  69  | 26   7  5    |
| 469   456  569 | 2 7  169 | 1368 38 3468 |
| 246   7    8   | 5 3  16  | 16   46 9    |
+----------------+----------+--------------+
| 38    2358 245 | 6 25 7   | 9    1  238  |
| 1     26   7   | 9 8  3   | 5    46 246  |
| 368   9    25  | 1 25 4   | 368  38 7    |
+----------------+----------+--------------+
| 5     36   16  | 4 9  8   | 7    2  136  |
| 34689 3468 69  | 7 1  2   | 368  5  368  |
| 7     28   12  | 3 6  5   | 4    9  18   |
+----------------+----------+--------------+

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



Joined: 27 Feb 2008
Posts: 20
Location: Tennessee, USA

PostPosted: Mon Feb 14, 2011 1:32 pm    Post subject: Reply with quote

I had slightly different basics and found an xyz wing on 126 in boxes 2 and 3. That did it for me.
Back to top
View user's profile Send private message
Marty R.



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

PostPosted: Mon Feb 14, 2011 4:41 pm    Post subject: Reply with quote

Like Stanley, I had a 2 in r3c7 and used the XYZ-Wing. However, in Hugh's grid the 16 pair in row 3 would knock out the other 6s in that row and finish it off.
Back to top
View user's profile Send private message
keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Mon Feb 14, 2011 4:57 pm    Post subject: Reply with quote

After basics:
Code:
+-------------------+-------------------+-------------------+
| 269   1     3     | 8     4     69    | 26    7     5     |
| 469   456   4569  | 2     7     169   | 1368  38    3468  |
| 246   7     8     | 5     3     16    | 126   46    9     |
+-------------------+-------------------+-------------------+
| 348   23458 245   | 6     25    7     | 9     1     2348  |
| 1     246   7     | 9     8     3     | 5     46    246   |
| 368   9     25    | 1     25    4     | 368   38    7     |
+-------------------+-------------------+-------------------+
| 5     36    16    | 4     9     8     | 7     2     136   |
| 34689 3468  469   | 7     1     2     | 368   5     368   |
| 7     28    12    | 3     6     5     | 4     9     18    |
+-------------------+-------------------+-------------------+
Keith
Back to top
View user's profile Send private message
cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Mon Feb 14, 2011 6:31 pm    Post subject: Reply with quote

R3C78 cannot be a 1 and 6 or a 2 and 6. Can only be a 1 and 4, 2 and 4, or 6 and 4. Ergo R3C8 has to be a 4.

I think that’s an APE (aligned pair exclusion). Better than looking for wings.
Back to top
View user's profile Send private message
Ema Nymton



Joined: 17 Apr 2009
Posts: 89

PostPosted: Tue Feb 15, 2011 1:17 pm    Post subject: Reply with quote

.

I conceed defeat. This is one subtle puzzle.

Code:

+------------------+----------+--------------+
| 269   1     3    | 8 4  69  | 26   7  5    |
| 469   456   4569 |*2 7  169 | 1368 38 368  |
| 26    7     8    | 5 3  16  | 126  4  9    |
+------------------+----------+--------------+
| 348   23458 245  | 6 25 7   | 9    1  2348 |
| 1     24    7    | 9 8  3   | 5    6  24   |
| 368   9     256  | 1 25 4   | 38   38 7    |
+------------------+----------+--------------+
| 5     36    16   | 4 9  8   | 7   *2  136  |
| 34689 3468  469  | 7 1  2   | 368  5  368  |
| 7     28    12   | 3 6  5   | 4    9  18   |
+------------------+----------+--------------+


The key was '2' in r2c4 and r7c8.
Thank you for the challenge.

Ema Nymton
.
Back to top
View user's profile Send private message
tlanglet



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

PostPosted: Tue Feb 15, 2011 3:59 pm    Post subject: Reply with quote

cgordon wrote:
R3C78 cannot be a 1 and 6 or a 2 and 6. Can only be a 1 and 4, 2 and 4, or 6 and 4. Ergo R3C8 has to be a 4.

I think that’s an APE (aligned pair exclusion). Better than looking for wings.


I agree with your analysis and that the pattern is an APE; it is also an xyz-wing as previously noted by Stanley and Marty. However I question your definition of "Better". In general, looking for an APE is more complex and cumbersome that looking for an xyz-wing, which is also frequently an APE pattern.

I guess "Better" truly depends on what motivates us to play Sudoku.

Ted
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