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Help for a Learner

 
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dbell

Joined: 21 Nov 2009
Posts: 2
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PostPosted: Sat Nov 21, 2009 5:22 pm    Post subject: Help for a Learner Reply with quote

I'm just getting into Sudoku solving by working the daily Universal Press puzzle printed in my newspaper. I'm hoping someone can tell me a technique to help me with todays puzzle.

Here is the original puzzle:

*-----------*
|..3|...|..8|
|5.4|21.|...|
|...|.6.|41.|
|---+---+---|
|.4.|3..|...|
|6.8|4.9|3.1|
|...|..5|.9.|
|---+---+---|
|.76|.5.|...|
|...|.94|2.5|
|4..|...|1..|
*-----------*

and my partial solution:

*-----------*
|..3|947|..8|
|5.4|218|.3.|
|...|563|41.|
|---+---+---|
|.4.|3..|...|
|6.8|4.9|3.1|
|...|..5|.94|
|---+---+---|
|.76|.5.|.43|
|..1|.94|2.5|
|4..|.3.|1..|
*-----------*

Any suggestions would be appreciated.
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sudoking

Joined: 20 Oct 2009
Posts: 40
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PostPosted: Sat Nov 21, 2009 8:35 pm    Post subject: Reply with quote

This will make it easier to read.

Code:

 *-----------------------*
 | . . 3 | 9 4 7 | . . 8 |
 | 5 . 4 | 2 1 8 | . 3 . |
 | . . . | 5 6 3 | 4 1 . |
 |-------+-------+-------|
 | . 4 . | 3 . . | . . . |
 | 6 . 8 | 4 . 9 | 3 . 1 |
 | . . . | . . 5 | . 9 4 |
 |-------+-------+-------|
 | . 7 6 | . 5 . | . 4 3 |
 | . . 1 | . 9 4 | 2 . 5 |
 | 4 . . | . 3 . | 1 . . |
 *-----------------------*


The first step would be to populate the candidates for each cell, like this:

Code:
+----------------+--------------+----------------+
|   12  126    3 |    9   4   7 |   56   256   8 |
|    5   69    4 |    2   1   8 |  679     3 679 |
| 2789  289  279 |    5   6   3 |    4     1 279 |
+----------------+--------------+----------------+
| 1279    4 2579 |    3 278 126 | 5678 25678 267 |
|    6   25    8 |    4  27   9 |    3   257   1 |
| 1237  123   27 | 1678 278   5 |  678     9   4 |
+----------------+--------------+----------------+
|  289    7    6 |   18   5  12 |   89     4   3 |
|   38   38    1 |  678   9   4 |    2   678   5 |
|    4 2589  259 |  678   3  26 |    1   678 679 |
+----------------+--------------+----------------+


There are several eliminations here. Then it starts to get tricky, requiring forced chains (according to sudoku explainer).
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daj95376

Joined: 05 Feb 2006
Posts: 349
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PostPosted: Sat Nov 21, 2009 8:55 pm    Post subject: Re: Help for a Learner Reply with quote

dbell wrote:
I'm just getting into Sudoku solving by working the daily Universal Press puzzle printed in my newspaper. I'm hoping someone can tell me a technique to help me with todays puzzle.

...

Any suggestions would be appreciated.

Many newspapers post easy puzzles early in the week and advanced puzzles for Friday and Saturday. That appears to be the case for your puzzle.

Code:
 +-----------------------+
 | . . 3 | . . . | . . 8 |
 | 5 . 4 | 2 1 . | . . . |
 | . . . | . 6 . | 4 1 . |
 |-------+-------+-------|
 | . 4 . | 3 . . | . . . |
 | 6 . 8 | 4 . 9 | 3 . 1 |
 | . . . | . . 5 | . 9 . |
 |-------+-------+-------|
 | . 7 6 | . 5 . | . . . |
 | . . . | . 9 4 | 2 . 5 |
 | 4 . . | . . . | 1 . . |
 +-----------------------+

Unfortunately, posting only your solved cells doesn't tell us about your eliminations in cells that weren't solved. I'm going to assume that you progressed to this point.

Code:
 +-----------------------------------------------------------------------+
 |  12     126    3      |  9      4      7      |  56     256    8      |
 |  5      69     4      |  2      1      8      |  679    3      679    |
 |  2789   289    279    |  5      6      3      |  4      1      29     |
 |-----------------------+-----------------------+-----------------------|
 |  1279   4      2579   |  3      278    16     |  5678   25678  267    |
 |  6      25     8      |  4      27     9      |  3      257    1      |
 |  1237   123    27     |  16     278    5      |  678    9      4      |
 |-----------------------+-----------------------+-----------------------|
 |  29     7      6      |  18     5      12     |  89     4      3      |
 |  38     38     1      |  67     9      4      |  2      67     5      |
 |  4      259    259    |  678    3      26     |  1      678    679    |
 +-----------------------------------------------------------------------+
 # 71 eliminations remain

At this point, I'd suggest using an (advanced) W-Wing pattern. Since you probably aren't familiar with the notation commonly used, I'll describe one way of understanding how it works on this puzzle.

Candidate <1> occurs only twice in row 4. Each sees a cell containing <12>.

Code:
r4c1=1 r1c1=2 r7c1<>2, or
r4c6=1 r7c6=2 r7c1<>2

In both cases, r7c1<>2 follows.

NOTE: you need to post future questions about puzzles in the Puzzles section.
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wapati

Joined: 12 Jun 2007
Posts: 622
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Location: Canada

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PostPosted: Sat Nov 21, 2009 11:50 pm    Post subject: Reply with quote

daj95376 wrote:

NOTE: you need to post future questions about puzzles in the Puzzles section.


Perhaps true.

This website might consider changes.


If some one comes here with a question about a puzzle should they go to:

A: Library>>Puzzles

B: Solving Sudoku

C: Another website
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sudoking

Joined: 20 Oct 2009
Posts: 40
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PostPosted: Sun Nov 22, 2009 3:19 pm    Post subject: Reply with quote

wapati wrote:
C: Another website


That should probably be reserved for those that hassle the noobies for posting questions on solving sudoku puzzles in the solving sudoku forum.
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m_b_metcalf

Joined: 13 Mar 2006
Posts: 210
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Location: Berlin

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PostPosted: Sun Nov 22, 2009 3:35 pm    Post subject: Reply with quote

sudoking wrote:
wapati wrote:
C: Another website


That should probably be reserved for those that hassle the noobies for posting questions on solving sudoku puzzles in the solving sudoku forum.


That should probably be reserved for those that hassle the noobies for posting questions on solving sudoku puzzles in the solving sudoku forum of the Programmers' Forum.

Regards,

Mike Metcalf
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dbell

Joined: 21 Nov 2009
Posts: 2
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PostPosted: Mon Nov 23, 2009 1:44 am    Post subject: Reply with quote

I apologize for posting my question in the wrong forum. I do appreciate the responses, however. I think this puzzle is beyond my level of comprehension at this time but I'll continue trying to learn some of these higher level techniques. Thanks.
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tarek

Joined: 31 Dec 2005
Posts: 153
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Location: London, UK

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PostPosted: Mon Nov 23, 2009 3:57 pm    Post subject: Reply with quote

you are also advised to visit http://www.sudoku.com/boards/index.php for advice regarding solving puzzles from an audience not involved with programming - Or from a player not wearing a programmers hat Very Happy -

tarek
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alb123456

Joined: 05 Dec 2009
Posts: 1
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PostPosted: Sat Dec 05, 2009 4:34 am    Post subject: alb123456 Reply with quote

hello
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Adak

Joined: 27 Feb 2008
Posts: 87
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PostPosted: Sat Dec 05, 2009 2:47 pm    Post subject: Reply with quote

Welcome to the forum, alb. Smile
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samuilov

Joined: 06 Feb 2010
Posts: 2
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PostPosted: Sat Feb 06, 2010 6:17 pm    Post subject: i like it here Reply with quote

hey guys i just wanna congratulate this community i am also a sudoku fan and i like solving puzzles
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samuilov

Joined: 06 Feb 2010
Posts: 2
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PostPosted: Sat Feb 06, 2010 6:18 pm    Post subject: aa Reply with quote

aaaa
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