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Collection August 23, 2012

 
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arkietech



Joined: 31 Jul 2008
Posts: 1719
Location: Northwest Arkansas USA

PostPosted: Thu Aug 23, 2012 5:05 am    Post subject: Collection August 23, 2012 Reply with quote

Code:

 *-----------*
 |..3|.7.|.4.|
 |7.5|.3.|..1|
 |2..|1..|...|
 |---+---+---|
 |1..|9..|4..|
 |9..|2.6|..7|
 |..6|..7|..2|
 |---+---+---|
 |...|..5|..8|
 |6..|.9.|3.5|
 |.7.|.6.|1..|
 *-----------*

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SudoQ



Joined: 02 Aug 2011
Posts: 127

PostPosted: Thu Aug 23, 2012 8:55 am    Post subject: Reply with quote

There are simpler steps, but this one has an additional value:
Code:
|---------------|------------------|--------------------|
| 8   1     3   | 56    7     29   | 2569   4       69  |
| 7   469   5   | 468   3     2489 | 2689   2689    1   |
| 2   469  (49) | 1     458   489  | 56789  356789  369 |
|---------------|------------------|--------------------|
| 1   2     7   | 9     58    38   | 4      3568    36  |
| 9   3458  8-4 | 2     1458  6    | 58     1358    7   |
| 3/4 3458  6   | 3458  1458  7    | 589    13589   2   |
|---------------|------------------|--------------------|
|/34  4/39  1   | 347   2     5    | 679    679     8   |
| 6   48    248 | 478   9     1    | 3      27      5   |
| 5   7    28/9 | 38    6     38   | 1      29      4   |
|---------------|------------------|--------------------|

If r3c3 is not 4 then r6c1 is 4.

/SudoQ
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arkietech



Joined: 31 Jul 2008
Posts: 1719
Location: Northwest Arkansas USA

PostPosted: Thu Aug 23, 2012 11:07 am    Post subject: Reply with quote

A new method.

For me anyway.

Code:

 *--------------------------------------------------------------------*
 | 8      1      3      | 56     7      2      | 56     4      9      |
 | 7     #49     5      | 68     3      49     | 2      68     1      |
 | 2      6      49     | 1      58     49     | 578    578    3      |
 |----------------------+----------------------+----------------------|
 | 1      2      7      | 9      58     38     | 4      358    6      |
 | 9      3458   48     | 2      14     6      | 58     1358   7      |
 | 34     3458   6      | 358    14     7      | 589    13589  2      |
 |----------------------+----------------------+----------------------|
 |#34    *349    1      | 47     2      5      | 679    679    8      |
 | 6     *48     248    | 47     9      1      | 3      27     5      |
 | 5      7      29     | 38     6      38     | 1      29     4      |
 *--------------------------------------------------------------------*
Aligned Pair Exclusion (APE)
r78c2 possibles 34*,38,48,94*,98
34 is not possible due to no remaining value for r7c1
94 is not possible due to no remaining value for r2c2
Therefore r8c2 cannot be a 4; stte

There is another APE in the grid. Can you find it?


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SudoQ



Joined: 02 Aug 2011
Posts: 127

PostPosted: Thu Aug 23, 2012 11:34 am    Post subject: Reply with quote

arkietech wrote:
A new method.


Isn't this a XYZ-wing?

/SudoQ
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arkietech



Joined: 31 Jul 2008
Posts: 1719
Location: Northwest Arkansas USA

PostPosted: Thu Aug 23, 2012 11:57 am    Post subject: Reply with quote

SudoQ wrote:
Isn't this a XYZ-wing?

Interesting Confused
Have the APES evolved? Very Happy
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Clement



Joined: 24 Apr 2006
Posts: 668
Location: Dar es Salaam Tanzania

PostPosted: Thu Aug 23, 2012 12:59 pm    Post subject: Collection August 23, 2012 Reply with quote

Also the W-Wing 48 with SL 4 in BOX 1; r56c2<>8 solves it.
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SudoQ



Joined: 02 Aug 2011
Posts: 127

PostPosted: Thu Aug 23, 2012 12:59 pm    Post subject: Reply with quote

arkietech wrote:
Interesting Confused
Have the APES evolved? Very Happy
Code:
|---------------|-------------|---------------|
| 8   1     3   | 56   7   2  | 56   4      9 |
| 7  (94)xz 5   | 68   3   49 | 2    68     1 |
| 2   6     49  | 1    58  49 | 578  578    3 |
|---------------|-------------|---------------|
| 1   2     7   | 9    58  38 | 4    358    6 |
| 9   3458  48  | 2    14  6  | 58   1358   7 |
| 34  3458  6   | 358  14  7  | 589  13589  2 |
|---------------|-------------|---------------|
| yz  xyz       |             |               |
|(34)(934)  1   | 47   2   5  | 679  679    8 |
| 6   8-4   248 | 47   9   1  | 3    27     5 |
| 5   7     29  | 38   6   38 | 1    29     4 |
|---------------|-------------|---------------|

The pattern and the result looked to be the same,
but method names are not my strong suit...

/SudoQ
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Clement



Joined: 24 Apr 2006
Posts: 668
Location: Dar es Salaam Tanzania

PostPosted: Thu Aug 23, 2012 1:04 pm    Post subject: Collection August 23, 2012 Reply with quote

Also the W-Wing 48 with SL 4 in BOX 1; r56c2<>8 solves it.
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arkietech



Joined: 31 Jul 2008
Posts: 1719
Location: Northwest Arkansas USA

PostPosted: Thu Aug 23, 2012 1:39 pm    Post subject: Reply with quote

The other one is not a clean xyz-wing.
Code:

 *--------------------------------------------------------------------*
 | 8      1      3      | 56     7      2      |*56     4      9      |
 | 7      49     5      | 68     3      49     | 2     #68     1      |
 | 2      6      49     | 1      58     49     |*57-8   578    3      |
 |----------------------+----------------------+----------------------|
 | 1      2      7      | 9      58     38     | 4      358    6      |
 | 9      3458   48     | 2      14     6      |#58     1358   7      |
 | 34     3458   6      | 358    14     7      | 589    13589  2      |
 |----------------------+----------------------+----------------------|
 | 34     349    1      | 47     2      5      | 679    679    8      |
 | 6      48     248    | 47     9      1      | 3      27     5      |
 | 5      7      29     | 38     6      38     | 1      29     4      |
 *--------------------------------------------------------------------*

APE:
r13c7 possibles 57,58*,65,67,68*
58 is not possible due to no remaining value for r5c7
68 is not possible due to no remaining value for r2c8
Therefore r3c7 cannot be an 8; doesn't solve the puzzle



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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Thu Aug 23, 2012 3:04 pm    Post subject: Reply with quote

I remember looking into Aligned Pair Exclusions early in my Sudoku experience. APE was noted to be "a hard to spot, laborious and complex technique which has a large overlap with easier techniques like xy-wing and xyz-wing". I quickly forgot it.......

In the two examples you posted, the first is identical to a xyz-wing. The second is overlaid by a xy-wing(56-8)r1c7+r2c8|r5c7 which has additional deletions to the one detected by the APE.

Ted
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Marty R.



Joined: 12 Feb 2006
Posts: 5160
Location: Rochester, NY, USA

PostPosted: Thu Aug 23, 2012 4:37 pm    Post subject: Reply with quote

I just played the XYZ-Wing.

A couple of years ago when APE was a hot topic here, Keith had some comments and I quote:

"APE is a monkey that you should not worry about.

I welcome any example of an APE exclusion that is not an XY... wing."
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arkietech



Joined: 31 Jul 2008
Posts: 1719
Location: Northwest Arkansas USA

PostPosted: Thu Aug 23, 2012 6:59 pm    Post subject: Reply with quote

Thanks guys for getting me up to date on the demise of the APE. Very Happy

Are there other methods worth a relook of to be forgotten? Confused
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Luke451



Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

PostPosted: Sat Aug 25, 2012 1:39 am    Post subject: Reply with quote

I agree that APE is a dead monkey, but since this is a slow news day...

First of all, I was under the impression that APE has been subsumed by ALS-xz, but I cannot gainsay Keith's "xy..." claim.

Anyways, for your your amusement, here's an example the kind of pushups we'd go through while ignoring the ALS-xz or wxyz wing (among other techniques) to utilize the APE.
Code:
*--------------------------------------------------------------------*
 | 3      9      57     | 4      28     258    | 6      178    18     |
 | 1      4      57     | 358    36     568    | 2      789    89     |
 | 8      26     26     | 9      7      1      | 34     5      34     |
 |----------------------+----------------------+----------------------|
 | 2479   38     1      | 6      28     45     | 34579 *239   *23459  |
 | 247    5      38     | 278    9      248    | 1347   6      1234   |
 | 24679  267    246    | 57     1      3      | 8      29     2459   |
 |----------------------+----------------------+----------------------|
 | 24     1      2348   | 238    5      7      | 39     2389   6      |
 | 257    2378   9      | 1238   36     268    | 135    4      12358  |
 | 256    2368   2368   | 1238   4      9      | 135    1238   7      |
 *--------------------------------------------------------------------*
APE with triples, r4c9<>2

The corresponding ALS-xz/wxyz-wing: (29=3)r46c8-(3=82)r4c25 ==>r4c9<>2
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