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Jellyfish - a rare species

 
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Wed May 28, 2008 2:41 pm    Post subject: Jellyfish - a rare species Reply with quote

Usually, the Times "Super Fiendish" sudoku can be solved using just x-wings or the odd swordfish. The February 15, 2008 puzzle number 1762, however, offered the rare opportunity to either use an xy-wing (38-23-28 in col 1 and row 9) or a jellyfish (3 rows 2,4,6,8 in cols 1,4,6,9).

For your convenience, I post a copy of the puzzle here:


Code:

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


play online
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tlanglet



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

PostPosted: Wed May 28, 2008 3:21 pm    Post subject: Reply with quote

Very interesting puzzle. Even knowing it contained a jellyfish, I did not spot it immediately. In fact, I noted the complimentary swordfish first and only after removing those eliminations did I see the jellyfish. Either eliminations actually solved the puzzle.

Thanks, nataraj, for a fun morning.

Ted
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Wed May 28, 2008 7:01 pm    Post subject: Reply with quote

Code:
.---------------------.---------------------.---------------------.
| 67     5      9     | 2      67     8     | 3      4      1     |
| 38     1      2     | 9      4      35    | 7      6      58    |
| 3678   4      368   | 3567   3567   1     | 28     9      258   |
:---------------------+---------------------+---------------------:
| 1689   7      168   | 346    2      34    | 146    5      39    |
| 4      3      156   | 8      56     9     | 16     2      7     |
| 569    2      56    | 34567  1      3457  | 46     8      39    |
:---------------------+---------------------+---------------------:
| 1235   89     135   | 3457   3579   23457 | 28     37     6     |
| 235    6      7     | 35     8      235   | 9      1      4     |
| 23     89     4     | 1      379    6     | 5      37     28    |
'---------------------'---------------------'---------------------'


nataraj, are you aware that the font inside your parenthesis is white? at least from my point of view. I actually didn't see it in a previous posting until I got really close to the monitor.
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Wed May 28, 2008 8:03 pm    Post subject: Reply with quote

storm_norm wrote:


nataraj, are you aware that the font inside your parenthesis is white? at least from my point of view. I actually didn't see it in a previous posting until I got really close to the monitor.


Yes, Norm. That is to avoid spoiling the fun for those who read the post but don't want to see the full solution right away. I did not find "invisible" color but white serves just fine.

And there is a better method to make the text visible: just highlight the text with the mouse - it will then stand out white on blue background. Definitely easier on the eyes ...

Glad you liked the puzzle Very Happy
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Wed May 28, 2008 8:57 pm    Post subject: Reply with quote

Quote:
That is to avoid spoiling the fun


of course !!

and yes, very nice fishy in there the 3's make up the jelly fish, and the swordfish mentioned.

can we expect more "unspoiled" solutions from you? Laughing
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Wed May 28, 2008 11:21 pm    Post subject: Reply with quote

How about this?

After basics:
Code:
+-------------------+-------------------+-------------------+
| 67    5     9     | 2     67    8     | 3     4     1     |
| 38a  1     2     | 9     4     35    | 7     6     5-8   |
| 367-8 4     36-8  | 3567  3567  1     | 28e   9     258   |
+-------------------+-------------------+-------------------+
| 1689  7     168   | 346   2     34    | 146   5     39    |
| 4     3     156   | 8     56    9     | 16    2     7     |
| 569   2     56    | 34567 1     3457  | 46    8     39    |
+-------------------+-------------------+-------------------+
| 1235  89    135   | 3457  3579  23457 | 28d   37    6     |
| 235   6     7     | 35    8     235   | 9     1     4     |
| 23b   89    4     | 1     379   6     | 5     37    28c   |
+-------------------+-------------------+-------------------+

The XY-wing abc can be extended to de. Any cell that sees both a and e cannot be <8>.

This is not essential to solve the puzzle, but these multiple eliminations of <8> make the end game much easier.

Keith
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