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Puzzle 11/05/14: ~ XY

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sun May 15, 2011 1:27 am    Post subject: Puzzle 11/05/14: ~ XY Reply with quote

Code:
 +-----------------------+
 | . . . | . . . | 1 3 2 |
 | . . 3 | 2 . . | . 9 4 |
 | . 2 4 | 9 . . | 7 . 6 |
 |-------+-------+-------|
 | . 7 9 | 4 . . | . . . |
 | . . . | . 2 . | . . 9 |
 | . . . | . . 9 | 4 . 3 |
 |-------+-------+-------|
 | 6 . 2 | . . 5 | 3 . 7 |
 | 4 9 . | . . . | . 6 . |
 | 5 3 7 | . 6 4 | 9 . 1 |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Sun May 15, 2011 11:19 am    Post subject: Reply with quote

A fun DP... that's assuming it is a DP, I'm on uncertain territory...
Code:
8-cell DP(58) r2c57, r3c58, r4c89, r8c79 ; r4c8<>5
(1)r4c8                - (5)r4c8
||
(3)r3c5 - (5)r3c5=r3c8 - (5)r4c8
||
(1)r2c5 - (1)r4c5=r4c8 - (5)r4c8
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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Sun May 15, 2011 2:16 pm    Post subject: Reply with quote

Peter, your pattern is a DP; more specifically it could be called an 8-cell AUR. Good spot...........

I also found the pattern and spent some time intrigued with the external sis which only included (8s). I finally abandoned that approach and found your solution looking at the internal inferences.

Noting that we had the same solution, I did the puzzle again.

While looking for xy-wings, I noticed this chain:
(7=8)r6c8-r3c8=r2c7-(8=1)r2c6-r2c5=r4c5-als(1=38)r5c61-(3=7)r5c4; r5c8,r6c5<>7

A BUG+1 or xy-wing (13-8) completes the puzzle.

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sun May 15, 2011 3:24 pm    Post subject: Reply with quote

A rare puzzle with L-Wing single-stepper but no suitably productive W/M/S-Wing.

Code:
 +-----------------------------------------------------+
 |  9    5    8    |  6    4    7    |  1    3    2    |
 |  7    6    3    |  2    158  18   |  58   9    4    |
 |  1    2    4    |  9    358  38   |  7    58   6    |
 |-----------------+-----------------+-----------------|
 |  38   7    9    |  4    138  6    |  2    158  58   |
 |  38   4    5    |  37   2    138  |  6    178  9    |
 |  2    1    6    |  5    78   9    |  4    78   3    |
 |-----------------+-----------------+-----------------|
 |  6    8    2    |  1    9    5    |  3    4    7    |
 |  4    9    1    |  37   37   2    |  58   6    58   |
 |  5    3    7    |  8    6    4    |  9    2    1    |
 +-----------------------------------------------------+
 # 26 eliminations remain

 L-Wing    (5)r2c5 = r2c7 - r3c8 = (5-1)r4c8 = (1)r4c5  =>  r2c5<>1
 L-Wing    (5)r2c5 = r3c5 - r3c8 = (5-1)r4c8 = (1)r4c5  =>  r2c5<>1
 L-Wing    (5)r4c8 = r3c8 - r2c7 = (5-1)r2c5 = (1)r4c5  =>  r4c8<>1
 L-Wing    (5)r4c8 = r3c8 - r3c5 = (5-1)r2c5 = (1)r4c5  =>  r4c8<>1
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ronk



Joined: 07 May 2006
Posts: 397

PostPosted: Sun May 15, 2011 4:30 pm    Post subject: Reply with quote

tlanglet wrote:
Peter, your pattern is a DP; more specifically it could be called an 8-cell AUR. Good spot...........

Agree on the "good spot", but it's a BUG-Lite, not an AUR.
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Marty R.



Joined: 12 Feb 2006
Posts: 5123
Location: Rochester, NY, USA

PostPosted: Mon May 16, 2011 4:18 am    Post subject: Reply with quote

XY-Wing (378); r5c6<>8
M-Wing (38), flightless with transport; r5c8<>8
BUG+1
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