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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Tue Apr 12, 2011 12:24 am Post subject: Puzzle 11/04/11: ~ Difficult |
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Code: | +-----------------------+
| . 4 . | . 3 . | . 9 2 |
| 5 3 . | . 9 . | 7 . 8 |
| . . 9 | . 8 . | 3 . 1 |
|-------+-------+-------|
| . . . | . . . | . . 4 |
| 1 5 4 | . . . | 2 . 9 |
| . . . | . . 4 | 1 . . |
|-------+-------+-------|
| . 2 5 | . 4 3 | . 1 . |
| 4 . . | . . . | 9 2 5 |
| 9 1 6 | 8 5 . | . 3 . |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Tue Apr 12, 2011 3:25 am Post subject: |
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Code: |
(6)r4c2=(6)r3c2-(6=2)r3c1-(2=1)r2c3-(1=6)r2c6-r1c46=(6)r1c7; r4c7<>6
\ /
-(6)r1c1 |
Ted |
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storm_norm
Joined: 18 Oct 2007 Posts: 1741
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Posted: Tue Apr 12, 2011 4:43 am Post subject: |
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tlanglet wrote: | Code: |
(6)r4c2=(6)r3c2-(6=2)r3c1-(2=1)r2c3-(1=6)r2c6-r1c46=(6)r1c7; r4c7<>6
\ /
-(6)r1c1 |
Ted |
not to nit pick. but this part of your structure
(6=2)r3c1-(2=1)r2c3-(1=6)r2c6
is an xy-chain that adds to your eliminations.
it removes the 6 in r3c6 |
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peterj
Joined: 26 Mar 2010 Posts: 974 Location: London, UK
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Posted: Tue Apr 12, 2011 8:12 am Post subject: |
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I initially played a skyscraper and then an xy-chain, but also found this one-stepper making the same elimination as Ted's ..
Code: | (6=5)r1c7 - r3c8=(5-7)r3c6=r3c2 - (7=6)r4c2 ; r4c7<>6 |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Tue Apr 12, 2011 12:14 pm Post subject: |
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storm_norm wrote: | tlanglet wrote: | Code: |
(6)r4c2=(6)r3c2-(6=2)r3c1-(2=1)r2c3-(1=6)r2c6-r1c46=(6)r1c7; r4c7<>6
\ /
-(6)r1c1 |
Ted |
not to nit pick. but this part of your structure
(6=2)r3c1-(2=1)r2c3-(1=6)r2c6
is an xy-chain that adds to your eliminations.
it removes the 6 in r3c6 |
Norm, Thanks for the comment. Actually, I initially spotted the xy-wing and while checking for additional deletions by transporting the pincers, I noted the full step. However, I was not sure how to notate the xy-wing deletion so I left it out.
Ted |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Tue Apr 12, 2011 1:21 pm Post subject: |
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tlanglet wrote: | Norm, Thanks for the comment. Actually, I initially spotted the xy-wing and while checking for additional deletions by transporting the pincers, I noted the full step. However, I was not sure how to notate the xy-wing deletion so I left it out.
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Suggestion:
...; r4c6<>6, r3c6<>6 (internal XY-Wing) |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Tue Apr 12, 2011 1:35 pm Post subject: |
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daj95376 wrote: | tlanglet wrote: | Norm, Thanks for the comment. Actually, I initially spotted the xy-wing and while checking for additional deletions by transporting the pincers, I noted the full step. However, I was not sure how to notate the xy-wing deletion so I left it out.
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Suggestion:
...; r4c6<>6, r3c6<>6 (internal XY-Wing) |
Danny, very nice suggestion.
Ted |
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Asellus
Joined: 05 Jun 2007 Posts: 865 Location: Sonoma County, CA, USA
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Posted: Tue Apr 12, 2011 6:48 pm Post subject: |
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It can be boiled down rather elegantly to:
XYWing[(6)r2c6=(6)r3c1] - Skyscraper[(6)r3c2=(6)r1c7]; r1c146|r2c8|r3c68<>6 |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Wed Apr 13, 2011 1:00 am Post subject: |
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Skyscraper; r1c1, r3c8<>6
XY-Wing (126), flightless with transport of each pincer; r4c7<>6 |
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