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 

An interesting Menneske

 
Post new topic   Reply to topic    dailysudoku.com Forum Index -> Other puzzles
View previous topic :: View next topic  
Author Message
keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Thu Mar 11, 2010 10:04 am    Post subject: An interesting Menneske Reply with quote
Code:
Puzzle: M6573410sh(13)
+-------+-------+-------+
| . 1 . | 4 2 8 | . . . |
| 7 . . | . 3 . | . . . |
| . 4 . | 7 . 5 | . . . |
+-------+-------+-------+
| 6 . 4 | . . . | 2 . 1 |
| 8 7 . | . . . | . 6 9 |
| 1 . 5 | . . . | 7 . 4 |
+-------+-------+-------+
| . . . | 9 . 6 | . . . |
| . . . | . 1 . | 5 . 6 |
| . . . | 2 7 4 | . 3 . |
+-------+-------+-------+
Keith
Back to top
View user's profile Send private message
tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Thu Mar 11, 2010 1:48 pm    Post subject: Reply with quote
I found some uncommon moves. Great Fun!

ALS A 1479 in r138c8
ALS B 149 in r79c7
shared exclusive = 9
shared common = 1 & 4 (which I guess is unusual)
r3c7<>1 & r7c8<>4

My understanding of MUGs is very shaky, but ......
Code:
 *--------------------------------------------------*
 | 359  1   #369  | 4    2    8    |#69   79   57   |
 | 7    56  #68   | 1    3    9    |#468  24   25   |
 | 2    4   #89   | 7    6    5    |#89   1    3    |
 |----------------+----------------+----------------|
 | 6    9    4    | 3    8    7    | 2    5    1    |
 | 8    7    2    | 5    4    1    | 3    6    9    |
 | 1    3    5    | 6    9    2    | 7    8    4    |
 |----------------+----------------+----------------|
 | 34   8    13   | 9    5    6    | 14   27   27   |
 | 49   2    7    | 8    1    3    | 5    49   6    |
 | 59   56   169  | 2    7    4    | 19   3    8    |
 *--------------------------------------------------*

MUG 689 in r123c37 marked #. To prevent the deadly pattern, either r1c3=3 or r2c7=4
(3-6)r1c3 = (6)r1c7
(4-6)r2c7 = (6)r1c7
Thus r1c7=6 under both constraints.

This results in a BUG+2 pattern that sets r1c1=9 & r9c3=9. These two pincers delete 9 in r13c3 and r89c1 to complete the puzzle.

Ted
Back to top
View user's profile Send private message
arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
PostPosted: Thu Mar 11, 2010 2:30 pm    Post subject: Reply with quote
There are several AIC or xy-chains that will solve this one in a single step. Here is one:
Code:
 *-----------------------------------------------------------*
 | 39-5  1     369   | 4     2     8     | 69   b79   a57    |
 | 7    g56    68    | 1     3     9     | 468   24    2-5   |
 | 2     4     89    | 7     6     5     | 189   19    3     |
 |-------------------+-------------------+-------------------|
 | 6     9     4     | 3     8     7     | 2     5     1     |
 | 8     7     2     | 5     4     1     | 3     6     9     |
 | 1     3     5     | 6     9     2     | 7     8     4     |
 |-------------------+-------------------+-------------------|
 | 34    8     137   | 9     5     6     | 14    1247  27    |
 | 49    2     79    | 8     1     3     | 5    c479   6     |
 |e59   f56    169   | 2     7     4     |d19    3     8     |
 *-----------------------------------------------------------*
(5=7)r1c9 - (7=9)r1c8 - r8c8 = r9c7 - (9=5)r9c1 - r9c2 = (5)r2c2;
r1c1,r2c9<>5
Back to top
View user's profile Send private message
tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Thu Mar 11, 2010 2:44 pm    Post subject: Reply with quote
A one step solution.

Code:
*-----------------------------------------------------------*
 | 359   1     369   | 4     2     8     | 69    79    57    |
 | 7     5-6  #68    | 1     3     9     |#468   24    25    |
 | 2     4     89    | 7     6     5     | 189   19    3     |
 |-------------------+-------------------+-------------------|
 | 6     9     4     | 3     8     7     | 2     5     1     |
 | 8     7     2     | 5     4     1     | 3     6     9     |
 | 1     3     5     | 6     9     2     | 7     8     4     |
 |-------------------+-------------------+-------------------|
 | 34    8     137   | 9     5     6     | 14    1247  27    |
 | 49    2     79    | 8     1     3     | 5     479   6     |
 | 59    56    169   | 2     7     4     | 19    3     8     |
 *-----------------------------------------------------------*


Note the two cells r2c37 marked #. Together they form an ALS, but they can also be viewed as an "almost" pair 68 with an extra digit 4 in r2c7. This arrangement has also been called a "hidden" pair. (How about the term "finned" pair?)

When viewed in this manner, either the 68 pair is true or r2c7=4 is true.
If the 68 pair is true, then r2c2<>6,
If r2c7=4 is true, then: (4)r2c7 - (4=1)r7c7 - (1=9)r9c7 - (9=5)r9c1 - (5=6)r9c2; r2c2<>6
Thus, both conditions result in r2c2<>6 to complete the puzzle.

Ted
Back to top
View user's profile Send private message
Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Thu Mar 11, 2010 8:25 pm    Post subject: Reply with quote
I played the 79 W-Wing, then finished with an XY-Chain very similar to Dan's which made the same elimination in r1c1.
Back to top
View user's profile Send private message
keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Thu Mar 11, 2010 8:55 pm    Post subject: Reply with quote
W-wing variants.

After basics:
Code:
+----------------+----------------+----------------+
| 359  1    369  | 4    2    8    | 69   79a  57   |
| 7    56   68   | 1    3    9    | 468  24   25   |
| 2    4    89   | 7    6    5    | 189  19   3    |
+----------------+----------------+----------------+
| 6    9    4    | 3    8    7    | 2    5    1    |
| 8    7    2    | 5    4    1    | 3    6    9    |
| 1    3    5    | 6    9    2    | 7    8    4    |
+----------------+----------------+----------------+
| 34   8    137  | 9    5    6    | 14   1247 27   |
| 49   2    79b  | 8    1    3    | 5   4-79  6    |
| 59   56   169  | 2    7    4    | 19   3    8    |
+----------------+----------------+----------------+
9 in a forces 7 in b, and 9 in b forces 7 in a. Taking out 7 in R8C8.
Code:
+-------------+-------------+-------------+
|3-59 1   369 | 4   2   8   | 69  79a 57b |
| 7   56  68  | 1   3   9   | 468 24  25  |
| 2   4   89  | 7   6   5   | 89  1   3   |
+-------------+-------------+-------------+
| 6   9   4   | 3   8   7   | 2   5   1   |
| 8   7   2   | 5   4   1   | 3   6   9   |
| 1   3   5   | 6   9   2   | 7   8   4   |
+-------------+-------------+-------------+
| 34  8   13  | 9   5   6   | 14  27  27  |
| 49@ 2   7   | 8   1   3   | 5   49@ 6   |
| 59c 56  169 | 2   7   4   | 19  3   8   |
+-------------+-------------+-------------+
ab are a pseudocell 59 forming a W-wing with c, taking out 5 in R1C1.

Keith
Back to top
View user's profile Send private message
tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Thu Mar 11, 2010 11:57 pm    Post subject: Reply with quote
keith wrote:
W-wing variants.

After basics:
Code:
+-------------+-------------+-------------+
|3-59 1   369 | 4   2   8   | 69  79a 57b |
| 7   56  68  | 1   3   9   | 468 24  25  |
| 2   4   89  | 7   6   5   | 89  1   3   |
+-------------+-------------+-------------+
| 6   9   4   | 3   8   7   | 2   5   1   |
| 8   7   2   | 5   4   1   | 3   6   9   |
| 1   3   5   | 6   9   2   | 7   8   4   |
+-------------+-------------+-------------+
| 34  8   13  | 9   5   6   | 14  27  27  |
| 49@ 2   7   | 8   1   3   | 5   49@ 6   |
| 59c 56  169 | 2   7   4   | 19  3   8   |
+-------------+-------------+-------------+
ab are a pseudocell 59 forming a W-wing with c, taking out 5 in R1C1.

Keith

Pseudocells to the rescue! Cool move Keith!

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 -> Other 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