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Puzzle 11/02/23 BBDB

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Wed Feb 23, 2011 5:54 pm    Post subject: Puzzle 11/02/23 BBDB Reply with quote
Code:
 +-----------------------+
 | . . 8 | 5 1 . | . 2 4 |
 | . . . | 4 7 . | . . 6 |
 | 2 . . | 6 . 9 | 5 . . |
 |-------+-------+-------|
 | 4 2 9 | . . . | . . . |
 | 5 8 . | . 4 . | . . 1 |
 | . . 7 | . . 5 | . . . |
 |-------+-------+-------|
 | . . 2 | . . . | 6 . . |
 | 7 . . | . . . | . 4 . |
 | 9 4 . | . 6 . | . . 5 |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Thu Feb 24, 2011 2:21 pm    Post subject: Reply with quote
Here is a 5-step solution.

x-wing (1)r37c28; r268c2,r29c8<>1
xy-wing 7-89 vertex (79)r1c7 plus transport: (8=9)r2c8-(9=7)r1c7-(7=8)r4c7*-r4c9=(8)r8c9; r2c7*,r9c8<>8
x-wing (2)r59c47; r8c47<>2
xy-wing 2-39 vertex (29)r5c4 plus transport: (3=9)r8c4-(9=2)r5c4-(2=3)r5c7*-r5c3=(3)r6c2; r8c7*,r8c2<>3

Code:
*--------------------------------------------------*
 | 6    7    8    | 5    1    3    | 9    2    4    |
 | 3    9    5    | 4    7    2    | 1    8    6    |
 | 2    1    4    | 6    8    9    | 5    37   37   |
 |----------------+----------------+----------------|
 | 4    2    9    | 1    3    6    | 7    5    8    |
 | 5    8    36   | 29   4    7    | 23   69   1    |
 | 1    36   7    | 8    29   5    | 4    69   23   |
 |----------------+----------------+----------------|
 | 8    35   2    | 379  59   4    | 6    1    379  |
 | 7    56   36   | 39   259  1    | 8    4    239  |
 | 9    4    1    | 237  6    8    | 23   37   5    |
 *--------------------------------------------------*


6-cell ADP(37)r3c89|r7c49|r9c48 sis r7c2=3,r9c7=3
ADP(37)r3c89|r7c49|r9c48[(3)r9c7=(3)r7c2]-r6c2=(3)r5c3; r5c7<>3

Ted
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ronk



Joined: 07 May 2006
Posts: 398
PostPosted: Thu Feb 24, 2011 11:53 pm    Post subject: Reply with quote
tlanglet wrote:
Code:
*--------------------------------------------------*
 | 6    7    8    | 5    1    3    | 9    2    4    |
 | 3    9    5    | 4    7    2    | 1    8    6    |
 | 2    1    4    | 6    8    9    | 5    37   37   |
 |----------------+----------------+----------------|
 | 4    2    9    | 1    3    6    | 7    5    8    |
 | 5    8    36   | 29   4    7    | 23   69   1    |
 | 1    36   7    | 8    29   5    | 4    69   23   |
 |----------------+----------------+----------------|
 | 8    35   2    | 379  59   4    | 6    1    379  |
 | 7    56   36   | 39   259  1    | 8    4    239  |
 | 9    4    1    | 237  6    8    | 23   37   5    |
 *--------------------------------------------------*


6-cell ADP(37)r3c89|r7c49|r9c48 sis r7c2=3,r9c7=3
ADP(37)r3c89|r7c49|r9c48[(3)r9c7=(3)r7c2]-r6c2=(3)r5c3; r5c7<>3

Nice "pseudo-ER" move. Smile
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Fri Feb 25, 2011 2:08 am    Post subject: Reply with quote
ronk wrote:
tlanglet wrote:
Code:
*--------------------------------------------------*
 | 6    7    8    | 5    1    3    | 9    2    4    |
 | 3    9    5    | 4    7    2    | 1    8    6    |
 | 2    1    4    | 6    8    9    | 5    37   37   |
 |----------------+----------------+----------------|
 | 4    2    9    | 1    3    6    | 7    5    8    |
 | 5    8    36   | 29   4    7    | 23   69   1    |
 | 1    36   7    | 8    29   5    | 4    69   23   |
 |----------------+----------------+----------------|
 | 8    35   2    | 379  59   4    | 6    1    379  |
 | 7    56   36   | 39   259  1    | 8    4    239  |
 | 9    4    1    | 237  6    8    | 23   37   5    |
 *--------------------------------------------------*


6-cell ADP(37)r3c89|r7c49|r9c48 sis r7c2=3,r9c7=3
ADP(37)r3c89|r7c49|r9c48[(3)r9c7=(3)r7c2]-r6c2=(3)r5c3; r5c7<>3

Nice "pseudo-ER" move. Smile


Ron,

Initially, I did not take the time to think about the pattern, but a "pseudo-ER" label is as good as any. Given your comment, I looked at it and my first reaction was a contradiction: (3)r9c7=(3)r5c7-r5c3=r6c2-ADP(37)r3c89|r7c49|r9c48[(3)r7c2=(3)r9c7]; contradiction! One of the wonders of sudoku is that different perspectives have identical results.

Ted
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Fri Feb 25, 2011 2:08 am    Post subject: Reply with quote
ronk wrote:
tlanglet wrote:
Code:
*--------------------------------------------------*
 | 6    7    8    | 5    1    3    | 9    2    4    |
 | 3    9    5    | 4    7    2    | 1    8    6    |
 | 2    1    4    | 6    8    9    | 5    37   37   |
 |----------------+----------------+----------------|
 | 4    2    9    | 1    3    6    | 7    5    8    |
 | 5    8    36   | 29   4    7    | 23   69   1    |
 | 1    36   7    | 8    29   5    | 4    69   23   |
 |----------------+----------------+----------------|
 | 8    35#  2    |-379  59@  4    | 6    1    379  |
 | 7    56  -36   | 39#  259  1    | 8    4    239  |
 | 9    4    1    | 237  6    8    | 23   37   5    |
 *--------------------------------------------------*


6-cell ADP(37)r3c89|r7c49|r9c48 sis r7c2=3,r9c7=3
ADP(37)r3c89|r7c49|r9c48[(3)r9c7=(3)r7c2]-r6c2=(3)r5c3; r5c7<>3

Nice "pseudo-ER" move. Smile

Unless you simply use the XY-wing -359. (Annotated by me in the quote.)

(And, I believe Ted's original step 4 R8C2 <>3 is not needed.)

Keith
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Fri Feb 25, 2011 5:47 am    Post subject: Reply with quote
keith wrote:
ronk wrote:
tlanglet wrote:
Code:
*--------------------------------------------------*
 | 6    7    8    | 5    1    3    | 9    2    4    |
 | 3    9    5    | 4    7    2    | 1    8    6    |
 | 2    1    4    | 6    8    9    | 5    37   37   |
 |----------------+----------------+----------------|
 | 4    2    9    | 1    3    6    | 7    5    8    |
 | 5    8    36   | 29   4    7    | 23   69   1    |
 | 1    36   7    | 8    29   5    | 4    69   23   |
 |----------------+----------------+----------------|
 | 8    35#  2    |-379  59@  4    | 6    1    379  |
 | 7    56  -36   | 39#  259  1    | 8    4    239  |
 | 9    4    1    | 237  6    8    | 23   37   5    |
 *--------------------------------------------------*


6-cell ADP(37)r3c89|r7c49|r9c48 sis r7c2=3,r9c7=3
ADP(37)r3c89|r7c49|r9c48[(3)r9c7=(3)r7c2]-r6c2=(3)r5c3; r5c7<>3

Nice "pseudo-ER" move. Smile

Unless you simply use the XY-wing -359. (Annotated by me in the quote.)

(And, I believe Ted's original step 4 R8C2 <>3 is not needed.)

Keith


Keith,

You are probably correct. I rarely go back and review my steps after completing a puzzle to determine if some of the them were unnecessary. In this puzzle, I had spotted the ADP(36) earlier but could not find a deletion so it was the first thing I checked following the second xy-wing.

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Fri Feb 25, 2011 7:59 am    Post subject: Reply with quote
Ted's ADP(37) based in internals:

Code:
                      r7c4=9 r7c5=5
                      r7c9=9 r7c5=5
 r9c4=2 r9c7=3 r9c8=7 r7c9=9 r7c5=5
 +-----------------------------------------------------+
 |  6    7    8    |  5    1    3    |  9    2    4    |
 |  3    9    5    |  4    7    2    |  1    8    6    |
 |  2    1    4    |  6    8    9    |  5   *37  *37   |
 |-----------------+-----------------+-----------------|
 |  4    2    9    |  1    3    6    |  7    5    8    |
 |  5    8    36   |  29   4    7    |  23   69   1    |
 |  1    36   7    |  8    29   5    |  4    69   23   |
 |-----------------+-----------------+-----------------|
 |  8    35   2    | *37+9 59   4    |  6    1   *37+9 |
 |  7    56   36   |  39   259  1    |  8    4    239  |
 |  9    4    1    | *37+2 6    8    |  23  *37   5    |
 +-----------------------------------------------------+
 # 27 eliminations remain
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