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arkietech
Joined: 31 Jul 2008 Posts: 1834 Location: Northwest Arkansas USA
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Posted: Mon Feb 27, 2012 1:57 pm Post subject: au 2/27/12 tough |
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Code: | *-----------*
|...|18.|...|
|..4|...|7..|
|2.8|...|.3.|
|---+---+---|
|7..|..4|..6|
|..6|.3.|2..|
|9..|5..|..3|
|---+---+---|
|.6.|...|4.8|
|..1|...|5..|
|...|.67|...|
*-----------* |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Mon Feb 27, 2012 3:53 pm Post subject: |
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Code: | *-----------------------------------------------------------*
| 6 357 357 | 1 8 235 | 9 245 245 |
| 15 1359 4 | 6 259 2359 | 7 8 125 |
| 2 159 8 | 47 47 59 | 6 3 15 |
|-------------------+-------------------+-------------------|
| 7 1358 35 | 289 129 4 | 18 59 6 |
| 1458 1458 6 | 789 3 189 | 2 4579 4579 |
| 9 148 2 | 5 17 6 | 18 47 3 |
|-------------------+-------------------+-------------------|
| 3 6 79 | 29 15 15 | 4 279 8 |
| 48 2478 1 | 3 249 289 | 5 6 279 |
| 458 2458 59 | 2489 6 7 | 3 1 29 |
*-----------------------------------------------------------*
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Two steps:
First, a SdC (24589)b7r9; r9c4<>29, r8c2<>48
which opens up a
xy-wing(79-2)r7c34+r8c2; r8c56<>2
to complete the puzzle.
Ted |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Mon Feb 27, 2012 4:35 pm Post subject: |
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Another perspective of my two step solution is that of a one step "almost xy-wing".
xy-wing(79-2)r7c34+r8c2=LS(48)r8c21-(48=5)r9c1-(5=9=2)r9c39-r7c8=r7c4; r8c56<>2
Ted |
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arkietech
Joined: 31 Jul 2008 Posts: 1834 Location: Northwest Arkansas USA
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Posted: Mon Feb 27, 2012 5:14 pm Post subject: |
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Here is a one stepper -- I think
Code: | *-----------------------------------------------------------*
| 6 357 357 | 1 8 235 | 9 245 245 |
| 15 1359 4 | 6 259 2359 | 7 8 125 |
| 2 159 8 | 47 47 59 | 6 3 15 |
|-------------------+-------------------+-------------------|
| 7 1358 35 | 289 129 4 | 18 59 6 |
| 1458 1458 6 | 789 3 189 | 2 4579 4579 |
| 9 148 2 | 5 17 6 | 18 47 3 |
|-------------------+-------------------+-------------------|
| 3 6 a79 |e2-9 15 15 | 4 d279 8 |
| 48 2478 1 | 3 249 289 | 5 6 279 |
| 458 2458 b59 | 2489 6 7 | 3 1 c29 |
*-----------------------------------------------------------*
s-wing
(9)r7c3=(9)r9c3-(9=2)r9c9-(2)r7c8=(2)r7c4 => r7c4<>9 |
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ronk
Joined: 07 May 2006 Posts: 398
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Posted: Mon Feb 27, 2012 6:10 pm Post subject: |
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Or keith's favorite, the w-wing: (2=9)r7c4 - (9)r7c3 = (9)r9c3 - (9=2)r9c9 ==> r7c8<>2, ste |
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SudoQ
Joined: 02 Aug 2011 Posts: 127
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Posted: Mon Feb 27, 2012 7:55 pm Post subject: |
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There is also a "crash & burn" solution:
r7c4=9 -> r7c3=7 -> .. -> r8c9=79
/SudoQ |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Tue Feb 28, 2012 4:36 pm Post subject: |
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I used the 29 W-Wing after staring at the grid forever before seeing it. |
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