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Puzzle 10/02/10 (B)

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Thu Feb 11, 2010 5:00 am    Post subject: Puzzle 10/02/10 (B) Reply with quote

XYZ-Wing alert.

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

Play this puzzle online at the Daily Sudoku site
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Marty R.



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

PostPosted: Fri Feb 12, 2010 2:19 am    Post subject: Reply with quote

Didn't notice any XYZs.

Quote:
X (2)
W (29)
X (7)
ER (9)
XY (479)
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Feb 12, 2010 8:43 am    Post subject: Reply with quote

sometimes Danny will show that an elimination of a x-wing candidate will solve the puzzle.
the same thing happens here on the x-wing 7.

here is the proof that the 7 in r2c3 cannot exist, in diagram form...
one of the candidates in r2c7 has to be true

Code:
(7)r2c7
||
(9)r2c7-(9)r13c8=(9)r9c8-(9)r8c79=(9)r8c6-(9)r7c4=(9)r7c3-(9=7)r6c3
||                                       |
||                                       |
(4)r2c7-(4)r9c7=(4)r9c6-(4)r8c6=(9)r8c6-/



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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Fri Feb 12, 2010 4:51 pm    Post subject: Reply with quote

Hello Norm. After basics, there doesn't seem to be anything reasonable to crack the puzzle. I see that you and Xsudoku have created a forcing network to attack the X-Wing c29\r26 for <7>. I just completed an upgrade to my chain() routine, and this lengthy chain is the best it could do. (including Eureka notation!)

Code:
 (7=9)r6c3 - r7c3 = r9c12 - (9=8)r9c8 - r1c8 = (8-6)r1c7 = (6-7)r3c7 = (7)r3c2 => r2c3,r4c2<>7
 +--------------------------------------------------------------+
 |  179   479   3     |  179   24    169   | f6789 e289   5     |
 |  1279  6     129-7 |  179   8     5     |  479   3     479   |
 |  8    h479   5     |  3     24    69    | g679   29    1     |
 |--------------------+--------------------+--------------------|
 |  1279  29-7  4     |  5     19    3     |  279   6     8     |
 |  6     5     129   |  8     19    7     |  3     4     29    |
 |  3     8    a79    |  4     6     2     |  5     1     79    |
 |--------------------+--------------------+--------------------|
 |  4     3    b29    |  29    7     8     |  1     5     6     |
 |  5     1     8     |  6     3     49    |  249   7     249   |
 | c279  c279   6     |  129   5     149   |  489  d89    3     |
 +--------------------------------------------------------------+
 # 65 eliminations remain
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Fri Feb 12, 2010 5:58 pm    Post subject: Reply with quote

Mine was even longer. Shocked
Code:
 *-----------------------------------------------------------*
 | 179   479   3     | 179   24    169   | 6789  289   5     |
 | 1279  6     1279  | 179   8     5     | 479   3     479   |
 | 8     479   5     | 3     24    69    | 679   29    1     |
 |-------------------+-------------------+-------------------|
 | 1279  279   4     | 5     19    3     | 279   6     8     |
 | 6     5     129   | 8     19    7     | 3     4     29    |
 | 3     8     79    | 4     6     2     | 5     1     79    |
 |-------------------+-------------------+-------------------|
 | 4     3     29    | 29    7     8     | 1     5     6     |
 | 5     1     8     | 6     3     49    | 249   7     249   |
 | 279   279   6     | 129   5     149   | 489   89    3     |
 *-----------------------------------------------------------*
(4)r8c9 = (4-7)r2c9 = (7)r6c9 - (7)r6c3 = (7)r2c3 - (7)r3c2 =
(7-6)r3c7 = (6-8)r1c7 = (8-4)r9c7 = (4)r9c6; r8c6,r9c7<>4
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Feb 12, 2010 6:14 pm    Post subject: Reply with quote

very nice both of ya
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