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Puzzle 11/07/09: ~ Extreme ?

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sat Jul 09, 2011 6:34 am    Post subject: Puzzle 11/07/09: ~ Extreme ? Reply with quote

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

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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Sat Jul 09, 2011 1:22 pm    Post subject: Reply with quote

Two steps - first is some sort of swordfish-variant...
Quote:
kraken skyscraper(9) ; skyscraper(9)[r8c2=r3c2-r3c6=r7c6]=r5c2 - r5c4=r4c5 ; r8c5<>9
AIC ; (2=1)r1c5 - r3c5=r3c2 - (1=8)r2c3 - r2c4=r3c4 - (8=2)r3c9 - r12c7=r4c7 ; r4c5<>2
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tlanglet



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

PostPosted: Sat Jul 09, 2011 6:32 pm    Post subject: Reply with quote

While chasing an anp(), I found a Kraken column which caused major damage.

Quote:
Kraken (9)r258c2; r8c5<>9=3
(9)r3c2-(9=26)r31c6-(2=9)r7c6;
(9)r5c2-r5c4=r4c5;
(9)r8c2;

(2=9)r3c1-r2c1=r2c5-r4c5=r4c9-(9=2)r6c9; r3c9<>2=8

Ted

[Edit: After posting my solution, I realized that the second step is a w-wing(29) with an extended strong link (9).]
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sat Jul 09, 2011 9:46 pm    Post subject: Reply with quote

Peter & Ted: I'm glad you had fun with this puzzle.
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tlanglet



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

PostPosted: Sat Jul 09, 2011 10:51 pm    Post subject: Reply with quote

daj95376 wrote:
Peter & Ted: I'm glad you had fun with this puzzle.


Danny, I enjoy all of your puzzles Exclamation Yes, some are even more fun than others, but I spend any available time working at them.

I also realize that recently I have not been telling you how enjoyable they have been. Sorry......

Ted
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susume



Joined: 13 May 2011
Posts: 36
Location: Southeastern US

PostPosted: Mon Jul 11, 2011 3:29 am    Post subject: Reply with quote

Danny, I just discovered your puzzles a week ago and am having great fun with them. This one took me 16 steps (gasp) and kept me intrigued for hours. I'm so glad you are posting them!
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Luke451



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

PostPosted: Mon Jul 11, 2011 5:22 am    Post subject: Reply with quote

peterj wrote:
Two steps - first is some sort of swordfish-variant...
Quote:
kraken skyscraper(9) ; skyscraper(9)[r8c2=r3c2-r3c6=r7c6]=r5c2 - r5c4=r4c5 ; r8c5<>9
AIC ; (2=1)r1c5 - r3c5=r3c2 - (1=8)r2c3 - r2c4=r3c4 - (8=2)r3c9 - r12c7=r4c7 ; r4c5<>2

Wow, Peter, you are great at finding these! Smile I am very interested in almost patterns of any kind within AICs, because they manufacture strong links.

I can see why you’d call it a kraken column, for all roads lead to Rome.

A certain ttt uses this concept a lot in very difficult puzzles. He calls them “fish,” as in turbot fish, I assume. Substituting “skyscraper” for “fish” is an accurate description. I've also seen you call them "ERs" (empty rectangles), which I don't quite get.

Here is how he has presented them in the past, just for interest:
Code:
 *--------------------------------------------------------------------*
 | 5      1236   168    | 7      123    26     | 128    9      4      |
 | 239    7      18     | 2389   12359  4      | 128    35     6      |
 | 239   *12369  4      | 2389   12359 *269    | 7      35     28     |
 |----------------------+----------------------+----------------------|
 | 4      16     16     | 5     *29     7      | 239    8      239    |
 | 8     *29     7      |*29     4      3      | 6      1      5      |
 | 239    5      239    | 6      8      1      | 4      7      29     |
 |----------------------+----------------------+----------------------|
 | 1      4      5      | 239    7     *29     | 389    6      389    |
 | 6     *239    239    | 1      3-9    8      | 5      4      7      |
 | 7      8      39     | 4      6      5      | 39     2      1      |
 *--------------------------------------------------------------------*

(9)r4c5=r5c4-r5c2=(fish 9’s: r8c2=r3c2-r3c6=r7c6) => r8c5<>9

Thanks for popularizing this idea, I gotta get on board.
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Mon Jul 11, 2011 6:46 am    Post subject: Reply with quote

Luke, names eh!
I am no expert in "fish" and normally when I post an "almost-turbot/fish" pattern where the chain only uses the same candidate digit, someone pipes up with an "actually thats a finned franken mutant swordfish" or something!

I have been inconsistent in my use of "er" I am afraid. On this board I normally restrict it to a chain with a strong link in row/col and a grouped strong link in a box; and use "turbot" for one with a pure strong link in a box.

[Edit. Deleted a "grandma to suck eggs" sentence]

Of course the AIC description is sufficient I just like to use the names!

As you say they often do a lot of damage, but some examples are I feel pretty easy to see.
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Marty R.



Joined: 12 Feb 2006
Posts: 5157
Location: Rochester, NY, USA

PostPosted: Wed Jul 13, 2011 11:50 pm    Post subject: Reply with quote

Unlike the previous Extreme, July 7, this one was too extreme for me and I punted at this point:

Code:

+-----------------+----------------+-------------+
| 5   1236  12368 | 7    123   26  | 1238 9  4   |
| 239 7     12389 | 2389 12359 4   | 1238 35 6   |
| 239 12369 4     | 2389 12359 269 | 7    35 238 |
+-----------------+----------------+-------------+
| 4    16    16   | 5    29    7   | 239  8  239 |
| 8   29    7     | 29   4     3   | 6    1  5   |
| 239 5     239   | 6    8     1   | 4    7  29  |
+-----------------+----------------+-------------+
| 1   4     5     | 239  7     29  | 389  6  389 |
| 6   239   239   | 1    39    8   | 5    4  7   |
| 7   8     39    | 4    6     5   | 39   2  1   |
+-----------------+----------------+-------------+

Play this puzzle online at the Daily Sudoku site
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