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arkietech
Joined: 31 Jul 2008 Posts: 1834 Location: Northwest Arkansas USA
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Posted: Wed May 02, 2012 5:51 am Post subject: Pattern game 6.48 tthsieh 5.2 |
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Code: |
*-----------*
|..1|2..|.3.|
|..4|1.5|..6|
|75.|4..|...|
|---+---+---|
|872|...|.4.|
|...|...|...|
|.6.|...|972|
|---+---+---|
|...|..1|.29|
|5..|3.4|6..|
|.2.|..6|3..|
*-----------*
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Play/Print online |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Wed May 02, 2012 2:44 pm Post subject: |
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For the first time in ages, I had the occasion to play Sudoku and found a solution that I am unable to formulate cleanly. I would appreciate any suggestions on how to specify this solution.
Code: | *--------------------------------------------------------------------*
| 69 89 1 | 2 689 7 | 45 3 45 |
| 2 389 4 | 1 389 5 | 7 89 6 |
| 7 5 c38-69 | 4 3689 389 | 2 189 18 |
|----------------------+----------------------+----------------------|
| 8 7 2 | 6 1359 39 | 15 4 35 |
| 39 14 359 | 57 13457 2 | 158 6 358 |
| 14 6 a35 |b58 14 38 | 9 7 2 |
|----------------------+----------------------+----------------------|
| 36 348 3678 | 578 578 1 | 48 2 9 |
| 5 189 89 | 3 2 4 | 6 18 7 |
| 14 2 78 | 9 78 6 | 3 5 14 |
*--------------------------------------------------------------------*
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Look at the axy-wing(35-8)r6c34+r3c3, marked abc, where r3c3 is viewed as two bivalues: 38 and 69. The xy-wing does not make any direct deletions, but does with a pincer transport: (8)r6c4-r6c6=r3c6 thereby making r3c589<>8.
The 69 bivalue in r3c3 is handled as follows:
ls(69)r3c3+r1c1-(9=3)r12c2-(3=48)r7c27-(8)r7c45=r9c5-r123c5=r3c6 thereby making r3c589<>8.
My current formulation is
[(8)r3c6=(8)r6c6-(8=5=3)r6c43-(3=8)r3c3]=[ls(69)r3c3+r1c1-(9=3)r12c2-(3=48)r7c27-(8)r7c45=r9c5-r123c5=r3c6]; r3c589<>8
Ted |
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JC Van Hay
Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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Posted: Wed May 02, 2012 3:55 pm Post subject: |
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tlanglet wrote: | ...I ... found a solution that I am unable to formulate cleanly. I would appreciate any suggestions on how to specify this solution. |
Eliminating redundant SIS, your step may be viewed as the following "wing" (or "Death Blossom") based on 3B1 :
r2c2=3 => NP(48)r7c27; r3c3=3 => NP(58)r6c34 :=> -8r7c4. Using the same idea as in (9=3)r12c2, one can write the following simple AIC :
Code: |
ALS (348)r7c27 : 8r7c27=3r7c2
3B1 : 3r2c2=3r3c3
ALS (358)r6c34 : 8r6c4========3r6c3
=> 8r7c27=8r6c4 :=> -8r7c4 |
If a name is wanted, one could call this a "pseudo-W Wing"
JC |
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daj95376
Joined: 23 Aug 2008 Posts: 3854
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Posted: Wed May 02, 2012 4:07 pm Post subject: |
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Ted, when you start in the middle, it's a good idea to start at one end and review your logic to the opposite end.
(8)r3c6=r6c6-(8=5)r6c4-(5=3)r6c3-r3c3=r2c2-(3=48)r7c27-(8)r7c45=r9c5-r123c5=r3c6 => r3c6=8 |
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arkietech
Joined: 31 Jul 2008 Posts: 1834 Location: Northwest Arkansas USA
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Posted: Wed May 02, 2012 4:16 pm Post subject: |
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JC Van Hay wrote: | If a name is wanted, one could call this a "pseudo-W Wing" |
I used a different approach.
Code: | *--------------------------------------------------------------------*
| 69 89 1 | 2 689 7 | 45 3 45 |
| 2 a89+3 4 | 1 389 5 | 7 89 6 |
| 7 5 e3689 | 4 3689 389 | 2 189 18 |
|----------------------+----------------------+----------------------|
| 8 7 2 | 6 1359 39 | 15 4 35 |
| 39 14 359 | 57 13457 2 | 158 6 358 |
| 14 6 35 | 58 14 38 | 9 7 2 |
|----------------------+----------------------+----------------------|
|c36 b348 d3678 | 578 578 1 | 48 2 9 |
| 5 189 89 | 3 2 4 | 6 18 7 |
| 14 2 78 | 9 78 6 | 3 5 14 |
*--------------------------------------------------------------------*
d-loop
(3)r2c2=r7c2-(3=6)r7c1-r7c3=(6-3)r3c3=(3)r2c2 => r2c2=3; lcls
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SudoQ
Joined: 02 Aug 2011 Posts: 127
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Posted: Wed May 02, 2012 5:31 pm Post subject: |
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Code: | r1c1=6 -> r7c1=3 ->
r3c3=6 -> r2c2=3 -> r7c2<>3
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/SudoQ |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Wed May 02, 2012 8:19 pm Post subject: |
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Took me four steps.
Skyscraper on 8
Multi-coloring on 8
M-Wing on 19
XY-Wing on 693 |
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tlanglet
Joined: 17 Oct 2007 Posts: 2468 Location: Northern California Foothills
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Posted: Thu May 03, 2012 12:52 am Post subject: |
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Thanks to everyone that offered different views and notational schemes. I find such feedback very informative.
Ted |
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aran
Joined: 19 Apr 2010 Posts: 70
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Posted: Thu May 03, 2012 10:51 am Post subject: |
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Remaining with tlanglet's original XY-wing (358 : r6c3+r3c3/r6c4) idea :
8r3c6=XYwing=3r2c2-(3=48)r7c27-8r7c4=r6c4-r6c6=r3c6 : =>r3c6=8
Too concise perhaps, but it's a matter of balancing between an off-putting chain and leaving a little work to the reader (should there be one).
As to whether brackets should precede XYwing in this chain ie 8r3c6=(XYwing=...=r3c6) :
I don't regard them as necessary : the XYwing can't exist, so it's not a possibility to be considered, and the only purpose of brackets in such circumstances is to introduce possibilities (generally two : x true/x false). |
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