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| Dralex
| Joined: 28 Mar 2006 | Posts: 7 | : | Location: Guenselsdorf, Austria | Items |
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Posted: Sat Jun 24, 2006 9:37 am Post subject: Two XY-wings in one? |
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Hello!
I had a nice extreme puzzle in SimpleSudoku. Standard methods brought me this far:
Code: |
*-----------*
|...|.52|..3|
|...|4.8|.2.|
|...|.3.|8..|
|---+---+---|
|69.|..5|24.|
|.2.|...|.1.|
|.14|2..|.89|
|---+---+---|
|..2|.9.|...|
|.6.|8.1|...|
|1..|76.|...|
*-----------*
*-----------*
|.81|.52|4.3|
|...|418|.2.|
|24.|.37|8.1|
|---+---+---|
|693|185|247|
|827|349|.1.|
|514|276|389|
|---+---+---|
|472|593|168|
|.6.|821|..4|
|1.8|764|..2|
*-----------*
*-----------------------------------------------------------*
| 79 8 1 | 69 5 2 | 4 79 3 |
| 379 35 569 | 4 1 8 | 5679 2 56 |
| 2 4 569 | 69 3 7 | 8 59 1 |
|-------------------+-------------------+-------------------|
| 6 9 3 | 1 8 5 | 2 4 7 |
| 8 2 7 | 3 4 9 | 56 1 56 |
| 5 1 4 | 2 7 6 | 3 8 9 |
|-------------------+-------------------+-------------------|
| 4 7 2 | 5 9 3 | 1 6 8 |
| 39 6 59 | 8 2 1 | 579 3579 4 |
| 1 35 8 | 7 6 4 | 59 39 2 |
*-----------------------------------------------------------*
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Now I see two XY-wings with R9C2 being the stem in both: one is
R8C1/R9C2/R9C7 and the other one is
R8C3/R9C2/R9C8.
These two XY-wings cannot both be true. How can I find out which is the right one?
Dralex[/code] _________________ Solving sudokus is really addictive |
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| rkral
| Joined: 21 Oct 2005 | Posts: 233 | : | | Items |
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Posted: Sat Jun 24, 2006 10:29 am Post subject: Re: Two XY-wings in one? |
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Dralex wrote: | one is
R8C1/R9C2/R9C7 and the other one is
R8C3/R9C2/R9C8.
These two XY-wings cannot both be true. |
Both XY-wings make the same exclusions, so there's no conflict that I can see. |
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| Carcul
| Joined: 29 Dec 2005 | Posts: 50 | : | Location: Coimbra, Portugal | Items |
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Posted: Sat Jun 24, 2006 12:01 pm Post subject: |
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Dralex, the hidden single in row 1 could perhaps simplify things a little.
Carcul |
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| Dralex
| Joined: 28 Mar 2006 | Posts: 7 | : | Location: Guenselsdorf, Austria | Items |
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Posted: Sat Jun 24, 2006 8:04 pm Post subject: |
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Hi Carcul,
Thank you. It did, when I took a hint which of course gave me that hidden single. How blind can a man get?
Dralex _________________ Solving sudokus is really addictive |
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