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MM 1573 10-30-09

 
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Fri Oct 30, 2009 11:00 pm    Post subject: MM 1573 10-30-09 Reply with quote

003069000024805000900030006500010780000000000071090004400000001000706420000180900

Code:

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

open in draw/play


open in andrew stuarts online solver
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Sat Oct 31, 2009 2:22 am    Post subject: Reply with quote

Code:
 *-----------------------------------------------------------*
 |*78    1     3     | 24    6     9     | 25-8  457   257   |
 | 6     2     4     | 8     7     5     | 1     9     3     |
 | 9     5-8   57-8  | 24    3     1     |*28    47    6     |
 |-------------------+-------------------+-------------------|
 | 5     4     6     | 3     1     2     | 7     8     9     |
 | 238   9     28    | 56    4     7     | 2356  1     25    |
 |b23    7     1     | 56    9     8     |c23    56    4     |
 |-------------------+-------------------+-------------------|
 | 4     58    578   | 9     2     3     | 56    567   1     |
 | 1     3     9     | 7     5     6     | 4     2     8     |
 |a27    6     257   | 1     8     4     | 9     3     57    |
 *-----------------------------------------------------------*
(8=7)r1c1-(7=2)r9c1-(2=3)r6c1-(3=2)r6c7-(2=8)r3c7
=> r1c7,r3c23<>8;
singles
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sat Oct 31, 2009 11:31 pm    Post subject: Reply with quote

A fun puzzle Exclamation

I noticed the DP 56 marked @.
Code:


 *-----------------------------------------------------------*
 | 78    1     3     | 24    6     9     | 258   457   257   |
 | 6     2     4     | 8     7     5     | 1     9     3     |
 | 9     58    578   | 24    3     1     | 28    47    6     |
 |-------------------+-------------------+-------------------|
 | 5     4     6     | 3     1     2     | 7     8     9     |
 | 238   9     28    | 56@   4     7     | 2356@ 1     25    |
 | 23    7     1     | 56@   9     8     | 23    56@   4     |
 |-------------------+-------------------+-------------------|
 | 4     58    578   | 9     2     3     | 56@   567@  1     |
 | 1     3     9     | 7     5     6     | 4     2     8     |
 | 27    6     257   | 1     8     4     | 9     3     57    |


To prevent the deadly DP either r5c7=23 or r7c8=7 to form the following chain. Please excuse the notation because it is suspect.

(5=7)r9c9 - DP56[(7)r7c8 = (23)r5c7] = (23)r56c7 - (2=5)r5c9; r1c9<>5,

I then needed a useless xy-wing -578 with pincer transport plus a xy-wing 2-47 to complete the puzzle.

Ted
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sat Oct 31, 2009 11:53 pm    Post subject: Reply with quote

ted,
that was nice.
I like those kind of eliminations.
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Myth Jellies



Joined: 27 Jun 2006
Posts: 64

PostPosted: Mon Nov 02, 2009 7:27 am    Post subject: Reply with quote

Actually, Ted, your deadly pattern is really like a type 6 UR. Note that the sixes are locked in the pattern. Thus if r6c8 was 5 then both of the deadly pattern avoidance cells would have to be 6 and the deadly pattern could not be avoided.

BUG(5&6#6)r5c47|r6c48|r7c78
||
(2|3)r5c7 - (6)r5c7 = (6)r6c8
||
(7)r7c8 - (6)r7c8 = (6)r6c8

or, if you prefer...

(6)r6c8 = (6-2|3)r5c7 =BUG= (7-6)r7c8 = (6)r6c8 => r6c8 <> 5
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Mon Nov 02, 2009 3:08 pm    Post subject: Reply with quote

It seems that sometimes the most obvious is the hardest to see. For me, this is a good example of having rushed to find a more complicated solution and not taking the time to fully evaluate the global nature of the code.

Thanks for the comments Myth.

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Mon Nov 02, 2009 4:22 pm    Post subject: Reply with quote

Ted: Nice Solution!

Myth Jellies: Thanks for illustrating how a locked/cyclic pattern for a digit influences a DP!

A slight variance on Myth Jellies' explanation:

If I color the <6>-cycle using Blue/Green, then the <56+23>,<56+7> cells are colored Green.

Setting any Blue cell to <5> would then force the DP.

Code:
 +---------------------------------------------------------------+
 |  78    1     3     |  24    6     9     |  258    457   257   |
 |  6     2     4     |  8     7     5     |  1      9     3     |
 |  9     58    578   |  24    3     1     |  28     47    6     |
 |--------------------+--------------------+---------------------|
 |  5     4     6     |  3     1     2     |  7      8     9     |
 |  238   9     28    | @56B   4     7     | @56G+23 1     25    |
 |  23    7     1     | @56G   9     8     |  23    @56B   4     |
 |--------------------+--------------------+---------------------|
 |  4     58    578   |  9     2     3     | @56B   @56G+7 1     |
 |  1     3     9     |  7     5     6     |  4      2     8     |
 |  27    6     257   |  1     8     4     |  9      3     57    |
 +---------------------------------------------------------------+
 # 36 eliminations remain
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