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Puzzle 11/06/19: ~ XY

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Mon Jun 20, 2011 2:47 am    Post subject: Puzzle 11/06/19: ~ XY Reply with quote

I found this puzzle in another file of puzzles where most are very difficult.

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

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: Mon Jun 20, 2011 9:56 pm    Post subject: Reply with quote

How about an "Almost Sue de Coq"

The code after basics:
Code:
 *-----------------------------------------------------------*
 | 6     1     57    | 48    379  @39(8) | 2349  29    3459  |
 | 39    4     57    | 2     67    1     | 39    8     56    |
 | 389   38    2     | 46    369   5     | 1     7     3469  |
 |-------------------+-------------------+-------------------|
 | 18    9     18    | 5     46    46    | 7     3     2     |
 | 4     2     3     | 9     1     7     | 6     5     8     |
 | 5     7     6     | 3     8     2     | 49    1     49    |
 |-------------------+-------------------+-------------------|
 | 238   368   4     | 1     5    *389   | 2389  269   7     |
 | 7     5     9     |#68    2    *368   | 38    4     1     |
 | 1238  368   18    | 7     349  *3489  | 5     269   39    |
 *-----------------------------------------------------------*

Assuming I understand a Sue de Coq as presented in the recent post by Keith, then
(abcde) is (34689)r789c6, marked *
(ab) is (39)r1c6, marked @
(cd) is (68)r8c4, marked #
(e) is (4)r9c6
with fin (8)r1c6

If the SdC is true then r4c6, r9c5<>4 are the only eliminations
If the fin is true: (8)r1c6-(8=4)r1c4-r1c79=r3c9-(4=9)r6c9-(9=3)r9c9-(3=8)r8c7-(8=6)r8c4-r8c6=r4c6-(6=4)r4c5; r4c6,r9c5<>4.

I have been looking for a SdC for a month and could not resist to post this one.

A Type 1 UR(18)r49c13 forces r9c1<>18=2 to complete the puzzle.

Ted
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Luke451



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

PostPosted: Tue Jun 21, 2011 12:42 am    Post subject: Reply with quote

tlanglet wrote:
How about an "Almost Sue de Coq" ?

Yeah, how about that Exclamation

DonM will be very happy when he sees your efforts. He might have written it as one AIC, starting with something like SDQ(34689)r8c4,r1789c6=(8)r1c6- and on into the chain you posted.

I'm very glad you put this up for another reason. I think I see now why a "naked" SDQ is subsumed by the doubly-linked ALS-xz. The former is always the latter, but certainly not the other way around.

Now how about a "non-SDQ almost doubly-linked ALS-xz?" Twisted Evil
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Tue Jun 21, 2011 5:42 am    Post subject: Reply with quote

Ted,

The SdC was interesting, but the chain for the fin candidate was OTT!!!

Regards, Danny
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peterj



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

PostPosted: Tue Jun 21, 2011 9:09 am    Post subject: Reply with quote

I played the humble w-wing(39) !

Looking at Ted's move and the fin, there's an als move (als-xy-wing?) that has the same effect ultimately as Ted's fin chain...

Code:
als(4=239)r1c78|r2c7 - (3=8)r8c7 - als(86=4)r38c4 ; r1c4<>4
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Marty R.



Joined: 12 Feb 2006
Posts: 5125
Location: Rochester, NY, USA

PostPosted: Wed Jun 22, 2011 4:20 am    Post subject: Reply with quote

I played the (apparently unneeded) Type 1 UR (18) before the puzzle-ending W-Wing (39).
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