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Puzzle 11/06/02: ~ XY (BBDB)

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Thu Jun 02, 2011 10:00 pm    Post subject: Puzzle 11/06/02: ~ XY (BBDB) Reply with quote

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

Play this puzzle online at the Daily Sudoku site
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tlanglet



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

PostPosted: Fri Jun 03, 2011 2:29 pm    Post subject: Reply with quote

Not sure how to notate this one step solution involving an "almost" AIC.

Code:
*--------------------------------------------------------------------*
 | 49     2      49     | 7      1      3      | 8      5      6      |
 | 5      8      7      | 49     2      6      | 149    149    3      |
 | 1      3      6      | 459    59     8      | 2      7      49     |
 |----------------------+----------------------+----------------------|
 | 2      49     35     | 6      8      579    | 34579  349    1      |
 | 6      7      35     | 1      4      59     | 359    2      8      |
 | 49     1      8      | 35     357    2      | 6      49     57     |
 |----------------------+----------------------+----------------------|
 | 7      49     2      | 8      359    1      | 3459   6     (45)9   |
 | 3      6      1      | 2      579    457    | 4579   8      4579   |
 | 8      5      49     | 39     6      47     | 13479  1349   2      |
 *--------------------------------------------------------------------*


View r7c9=45 with fin (9)

If r7c9=45 then (5=3)r6c4-(3=9)r9c4-r23c4=r3c5-(9=4)r3c9-(4=5)r7c9; r6c9<>5
If r7c9=9 then (9)r7c9-r7c2=r9c3-(9=3)r9c4-(3=5)r6c4; r6c9<>5

Also, a Kraken x-wing(5)r36c45 with Kraken fin (5)r6c9 results in r7c5<>5 which then leads to r7c9<>9
If Kraken fin is true: (5)r6c9-(5=3)r6c3-r6c5=(3-5)r7c5;

Ted
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peterj



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

PostPosted: Fri Jun 03, 2011 2:49 pm    Post subject: Reply with quote

I became obsessed with all those 49s! An oddagon/impossible-loop and a remote-pair entwined...
Code:
*--------------------------------------------------------------------*
 | 49     2      49     | 7      1      3      | 8      5      6      |
 | 5      8      7      | 49     2      6      | 149   *49+1   3      |
 | 1      3      6      | 459    59     8      | 2      7     *49     |
 |----------------------+----------------------+----------------------|
 | 2     *49     35     | 6      8      579    | 34579  349    1      |
 | 6      7      35     | 1      4      59     | 359    2      8      |
 |*49     1      8      | 35     357    2      | 6     *49     7-5    |
 |----------------------+----------------------+----------------------|
 | 7     *49     2      | 8      359    1      | 3459   6     *49+5   |
 | 3      6      1      | 2      579    457    | 4579   8      4579   |
 | 8      5      49     | 39     6      47     | 13479  1349   2      |
 *--------------------------------------------------------------------*
Oddagon creates a strong link (5)r7c9=(1)r2c8
Code:
*--------------------------------------------------------------------*
 | 49     2      49     | 7      1      3      | 8      5      6      |
 | 5      8      7      |*49     2      6      |*49+1   149    3      |
 | 1      3      6      | 459    59     8      | 2      7     *49     |
 |----------------------+----------------------+----------------------|
 | 2      49     35     | 6      8      579    | 34579  349    1      |
 | 6      7      35     | 1      4      59     | 359    2      8      |
 | 49     1      8      |(35)    357    2      | 6      49     7-5    |
 |----------------------+----------------------+----------------------|
 | 7     *49     2      | 8      359    1      | 3459   6     *49+5   |
 | 3      6      1      | 2      579    457    | 4579   8      4579   |
 | 8      5     *49     |(39)    6      47     | 13479  1349   2      |
 *--------------------------------------------------------------------*
Almost-remote-pair would eliminate (9)r9c4 making r6c4=5

The fins and guardians are clearly intertwined!

Consider the oddagon/impossible-loop...
Either (5)r7c9 ...
or if not then (1)r2c8 ... so r2c7<>1 & r7c9<>5 and the remote-pair exists, so r6c4=5

In either case, r6c9<>5!

As an "AIC"...
Code:
oddagon(49)[(5)r7c9=(1)r2c8] - (1)r2c7&(5)r7c9=remotepair(49) - (9=3)r9c4 - (3=5)r6c4 ; r6c9<>5

Having wasted 30 mins of my life on a pair of digits, I went back to find a humbling-ly simple two-stepper (which didn't include any remote pairs)!
Quote:
xyz-wing(35-9)r7c5 ; r8c5<>9
w-wing(49) r7c2, r3c9 ; r7c9<>4

Ted, it looks like what SE would call a "cell forcing chain"? Same elimination as a bove and some similar fragments.
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Fri Jun 03, 2011 6:06 pm    Post subject: Reply with quote

It's interesting how peterj's second solution reduced the six steps from my solver to two necessary steps.

My solver also listed this single-stepper SIN: 5r6c9 5r3c4 4r3c9 9r7c9 9r8c5 => [r3c5]=EMPTY

Which led me to this simple Kraken Cell scenaro:

Code:
 (4)r7c9 - (4=9)r3c9          - (  9)r3c5
 (5)r7c9 - r6c9 = r6c4 - r3c4 = (5-9)r3c5
 (9)r7c9 - r8c79 = r8c5       - (  9)r3c5
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Marty R.



Joined: 12 Feb 2006
Posts: 5161
Location: Rochester, NY, USA

PostPosted: Sun Jun 05, 2011 4:40 am    Post subject: Reply with quote

XYZ-Wing (359); r8c5<>9
XY-Wing (495), flightless with transport; r6c9<>5
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