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Set XY_03 Puzzle 008

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sat May 30, 2009 4:40 pm    Post subject: Set XY_03 Puzzle 008 Reply with quote

Code:
 +-----------------------+
 | . 7 . | 1 . 6 | 4 . 9 |
 | 6 . . | . 4 . | 2 . . |
 | . . 3 | . . 8 | 7 6 . |
 |-------+-------+-------|
 | 3 . . | 4 . . | . . . |
 | . 9 . | . 8 2 | . . . |
 | 8 . 6 | . 7 . | . 2 . |
 |-------+-------+-------|
 | 1 6 2 | . . . | 9 . . |
 | . . 8 | . . 4 | . . . |
 | 4 . . | . . . | . . 8 |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sun May 31, 2009 8:44 am    Post subject: Reply with quote

Danny,
found another "almost w-wing"
the cells marked "w" below would contain a w-wing on {56} with conjugate 6's in column 5 if the 3 was false in r9c7. right?
if the W-wing is true
{(5=6)r4c9 - (6)r4c5 = (6)r9c5 - (5=6)r9c7} means r6c7 <> 5
Code:
.------------------.------------------.------------------.
| 2     7     5    | 1     3     6    | 4     8     9    |
| 6     8     1    | 7     4     9    | 2     35    35   |
| 9     4     3    | 5     2     8    | 7     6     1    |
:------------------+------------------+------------------:
| 3     2     7    | 4    W16    15   | 8     9    W56   |
| 5     9     4    | 36    8     2    | 13    137   367  |
| 8     1     6    | 9     7    *35   |3-5    2     4    |
:------------------+------------------+------------------:
| 1     6     2    | 8     5    *37   | 9     4    *37   |
| 7     35    8    | 36    9     4    | 1356  135   2    |
| 4     35    9    | 2    W16    137  |W356   357   8    |
'------------------'------------------'------------------'

if the w-wing is false, then the 3 in r9c7 is true
leads too the cells marked "*"
(w-wing false) = (3)r9c7 - (3=7)r7c9 - (7=3)r7c6 - (3=5)r6c6; means r6c7 <> 5

both ways say r6c7 <> 5
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wapati



Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.

PostPosted: Sun May 31, 2009 3:35 pm    Post subject: Reply with quote

That is both good and funny.

ALS, various Almost URs and now Almost W-wings.

Are there Almost Almost deductions yet ? Wink
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sun May 31, 2009 3:55 pm    Post subject: Reply with quote

storm_norm wrote:
Danny,
found another "almost w-wing"
the cells marked "w" below would contain a w-wing on {56} with conjugate 6's in column 5 if the 3 was false in r9c7. right?
if the W-wing is true
{(5=6)r4c9 - (6)r4c5 = (6)r9c5 - (5=6)r9c7} means r6c7 <> 5
Code:
.------------------.------------------.------------------.
| 2     7     5    | 1     3     6    | 4     8     9    |
| 6     8     1    | 7     4     9    | 2     35    35   |
| 9     4     3    | 5     2     8    | 7     6     1    |
:------------------+------------------+------------------:
| 3     2     7    | 4    W16    15   | 8     9    W56   |
| 5     9     4    | 36    8     2    | 13    137   367  |
| 8     1     6    | 9     7    *35   |3-5    2     4    |
:------------------+------------------+------------------:
| 1     6     2    | 8     5    *37   | 9     4    *37   |
| 7     35    8    | 36    9     4    | 1356  135   2    |
| 4     35    9    | 2    W16    137  |W356   357   8    |
'------------------'------------------'------------------'

if the w-wing is false, then the 3 in r9c7 is true
leads too the cells marked "*"
(w-wing false) = (3)r9c7 - (3=7)r7c9 - (7=3)r7c6 - (3=5)r6c6; means r6c7 <> 5

both ways say r6c7 <> 5

Right!

Rambling:

Since everything hinges on [r9c7]=3 or [r9c7]<>3, it works as a forcing chain for me:

(3)r9c7 = ( <56> W-Wing ) - (5)r6c7

(3)r9c7 - r7c9 = r7c6 - (3=5) r6c6 - (5)r6c7

I'm guessing this approach was more fun than using the Skyscraper r67\c6 on <3> and then performing the W-Wing.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sun May 31, 2009 6:18 pm    Post subject: Reply with quote

Quote:
I'm guessing this approach was more fun than using the Skyscraper r67\c6 on <3> and then performing the W-Wing.

sure, it would be fun to accomplish those steps.
but naturally as soon as the statement is made that they were fun, then someone would post that it wasn't fun.

and...

naturally, if the statement was made that those steps weren't fun, then a post is almost assuredly coming that claims the steps were fun.
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sun May 31, 2009 8:07 pm    Post subject: Reply with quote

storm_norm wrote:
Quote:
I'm guessing this approach was more fun than using the Skyscraper r67\c6 on <3> and then performing the W-Wing.

sure, it would be fun to accomplish those steps.
but naturally as soon as the statement is made that they were fun, then someone would post that it wasn't fun.

and...

naturally, if the statement was made that those steps weren't fun, then a post is almost assuredly coming that claims the steps were fun.

Well, it looks like I stepped in it with my statement. I was just expecting you to say that it was more fun for you.

My apologies, Danny
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sun May 31, 2009 10:52 pm    Post subject: Reply with quote

daj95376 wrote:
storm_norm wrote:
Quote:
I'm guessing this approach was more fun than using the Skyscraper r67\c6 on <3> and then performing the W-Wing.

sure, it would be fun to accomplish those steps.
but naturally as soon as the statement is made that they were fun, then someone would post that it wasn't fun.

and...

naturally, if the statement was made that those steps weren't fun, then a post is almost assuredly coming that claims the steps were fun.

Well, it looks like I stepped in it with my statement. I was just expecting you to say that it was more fun for you.

My apologies, Danny


nah, you didn't step in it.
it was fun finding it.
I am only posting about this pattern in order to get it out into the court of public opinion. not because I think its really really fun. Cool Cool Cool

addictive is a better adjective.
a word in which you find very familiar when it comes to sudoku?? Danny?
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sun May 31, 2009 11:28 pm    Post subject: Reply with quote

storm_norm wrote:
nah, you didn't step in it.
it was fun finding it.
I am only posting about this pattern in order to get it out into the court of public opinion.

Opinion: I find these patterns interesting, but only if they occur when other, more reasonable techniques aren't available. With the Skyscraper being present, it tarnishes your example (for me).
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Mon Jun 01, 2009 6:25 am    Post subject: Reply with quote

daj95376 wrote:
storm_norm wrote:
nah, you didn't step in it.
it was fun finding it.
I am only posting about this pattern in order to get it out into the court of public opinion.

Opinion: I find these patterns interesting, but only if they occur when other, more reasonable techniques aren't available. With the Skyscraper being present, it tarnishes your example (for me).


I'd agree with you except that my example does solve your puzzle in one step. which means that the skyscraper is not needed to solve your puzzle.
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Tue Jun 02, 2009 12:23 am    Post subject: Reply with quote

I used a W-Wing on 35, then looked at the possibilities on a Type 3 UR on 35. Two of the possibilities were invalid, reducing it to a Type 1 which finished it off.
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