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Puzzle 11/08/09: ~ XY (BBDB?) (difficult!)

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Tue Aug 09, 2011 9:49 pm    Post subject: Puzzle 11/08/09: ~ XY (BBDB?) (difficult!) Reply with quote

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

Play this puzzle online at the Daily Sudoku site
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Luke451



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

PostPosted: Wed Aug 10, 2011 4:31 am    Post subject: Reply with quote

If a black bug bleeds black blood, what color blood does a blue bug bleed?
Code:
 *-----------------------------------------------------------*
 | 2     7     6     | 348   34    9     | 48    1     5     |
 | 3     8     4     | 2     5     1     | 67    67    9     |
 | 5     9     1     | 478   467   4678  | 48    2     3     |
 |-------------------+-------------------+-------------------|
 | 1     4     28    | 9     367   2367  | 5     678   678   |
 | 9     6     5     | 147   8     47    | 2     3     147   |
 | 7     3     28    | 145   46    2456  | 9     468   1468  |
 |-------------------+-------------------+-------------------|
 | 4     2     9     | 6     1     78    | 3     5     78    |
 | 8     1     3     | 457   2     457   | 67    9     467   |
 | 6     5     7     | 348   9     348   | 1     48    2     |
 *-----------------------------------------------------------*

BUG-Lite (67)r2c78,r4c89,r8c79[(8)r4c89=(4)r8c9]:

1. (8)r6c3=r4c3-[(8)r4c89=(4)r8c9]-(4=8)r9c8 =>r6c8<>8
2. xy: (8=4)r9c8-(4=6)-(6=4)-(4=7)-(7=8)r7c6 =>r7c9<>8
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Wed Aug 10, 2011 6:41 am    Post subject: Reply with quote

Luke451 wrote:
BUG-Lite (67)r2c78,r4c89,r8c79[(8)r4c89=(4)r8c9]:

1. (8)r6c3=r4c3-[(8)r4c89=(4)r8c9]-(4=8)r9c8 =>r6c8<>8
2. xy: (8=4)r9c8-(4=6)-(6=4)-(4=7)-(7=8)r7c6 =>r7c9<>8

Luke, nice find on the BUG-Lite. Can the first chain be shortened?

(8)r6c3=r4c3-[(8)r4c89=(4)r8c9]-(4=8)r9c8 =>r6c8<>8
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Luke451



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

PostPosted: Wed Aug 10, 2011 1:32 pm    Post subject: Reply with quote

daj95376 wrote:
Luke451 wrote:
BUG-Lite (67)r2c78,r4c89,r8c79[(8)r4c89=(4)r8c9]:

1. (8)r6c3=r4c3-[(8)r4c89=(4)r8c9]-(4=8)r9c8 =>r6c8<>8
2. xy: (8=4)r9c8-(4=6)-(6=4)-(4=7)-(7=8)r7c6 =>r7c9<>8

Luke, nice find on the BUG-Lite. Can the first chain be shortened?

(8)r6c3=r4c3-[(8)r4c89=(4)r8c9]-(4=8)r9c8 =>r6c8<>8

Sure can, that first part was left over from a failed attempt to combine the two moves, should have been clipped. Thanks.

So now, if we are now calling little wings things like a "Purple Cow" based on someone's whim, I'm going ahead by claiming further naming rights.

This particular BUG-Lite will hereafter and into perpetuity be known as the "Blue Blood BUG." Thank you very much. I look forward to the Sudopedia revisions, articles on "Extended Blue Blood BUGS," glory and recognition.

Twisted Evil Wink Wink Twisted Evil
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ronk



Joined: 07 May 2006
Posts: 397

PostPosted: Wed Aug 10, 2011 1:55 pm    Post subject: Reply with quote

Luke451 wrote:
So now, if we are now calling little wings things like a "Purple Cow" based on someone's whim, I'm going ahead by claiming further naming rights.

You'll find no support for the "purple cow" name from me ... and I've been astounded at its usage by others. Shocked Sad
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Wed Aug 10, 2011 4:42 pm    Post subject: Reply with quote

Luke451 wrote:
So now, if we are now calling little wings things like a "Purple Cow" based on someone's whim, I'm going ahead by claiming further naming rights.

This particular BUG-Lite will hereafter and into perpetuity be known as the "Blue Blood BUG." Thank you very much. I look forward to the Sudopedia revisions, articles on "Extended Blue Blood BUGS," glory and recognition.

Twisted Evil Wink Wink Twisted Evil

Luke,

I'm glad to see someone having fun with the trend to name interesting patterns. I must admit that I participated, some. I also must admit that this is an interesting pattern, and that it's tempting to stick a label on it. Thanks for the chuckle!!!

BTW: The Purple Cow thing confused me from the start.

Regards, Danny
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Marty R.



Joined: 12 Feb 2006
Posts: 5062
Location: Rochester, NY, USA

PostPosted: Thu Aug 11, 2011 5:59 pm    Post subject: Reply with quote

I'm stuck. I played the Bug-Lite (I still like to call it a potential DP) but the eliminations didn't set up a move that I could see. I don't understand what Luke did with the Bug-Lite, but his subsequent chain set r6c8<>8, which i thought was accomplished by the Bug-Lite.
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Luke451



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

PostPosted: Fri Aug 12, 2011 2:17 am    Post subject: Reply with quote

Marty R. wrote:
I'm stuck. I played the Bug-Lite (I still like to call it a potential DP) but the eliminations didn't set up a move that I could see. I don't understand what Luke did with the Bug-Lite, but his subsequent chain set r6c8<>8, which i thought was accomplished by the Bug-Lite.


Hi, Marty, thanks for looking past my shenanigans and at the actual puzzle Smile

Did you mean to say you do or don't understand what was done with BUG-Lite? r6c8<>8 is accomplished by the BUG-Lite, as you pointed out.

The second chain (xy) proves r7c9<>8.

If what was done with the BUG-Lite is confusing, I will elaborate to the best of my shaky ability.
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Marty R.



Joined: 12 Feb 2006
Posts: 5062
Location: Rochester, NY, USA

PostPosted: Fri Aug 12, 2011 3:48 am    Post subject: Reply with quote

Quote:
Hi, Marty, thanks for looking past my shenanigans and at the actual puzzle Smile

Did you mean to say you do or don't understand what was done with BUG-Lite? r6c8<>8 is accomplished by the BUG-Lite, as you pointed out.

The second chain (xy) proves r7c9<>8.

If what was done with the BUG-Lite is confusing, I will elaborate to the best of my shaky ability.

Luke,

First of all, I'm notation-challenged. But I can now see in your post that the first line like was a heading, or intro, not a separate step. I was thinking that the chain that eliminated 8 from r6c8 was step #2 as opposed to the elimination from the Bug-Lite.
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peterj



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

PostPosted: Fri Aug 12, 2011 8:01 am    Post subject: Reply with quote

An alternative non-DP two stepper...
Code:
m-wing-like(48) (4=78)r57c6 - r7c9=(8-4)r9c8=r6c8 ; r6c456<>4, r5c9<>4
xyz-wing(68-7) r4c9, r4c8, r7c9 ; r5c9<>7

For fun a one-stepper admittedly cobbled together from another path in my notes.. and trying too hard!
Code:
xyz-wing(45-7)r8c6,r8c4,r5c6=(4)r8c4 - (348=7)r193c4 - r3c5=r4c5 - (678=4)r4c89|r6c6 - (4=8)r9c8 - (8=7)r7c9 ; r7c6<>7

(Couple of almost-xyz-wings in these two paths)
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Fri Aug 12, 2011 4:43 pm    Post subject: Reply with quote

My solver used a long XY-Chain on this puzzle to keep it XY-rated.

Alternately:

Code:
 after basics:
 +--------------------------------------------------------------+
 |  2     7     6     |  348   34    9     |  48    1     5     |
 |  3     8     4     |  2     5     1     |  67    67    9     |
 |  5     9     1     |  478   467   4678  |  48    2     3     |
 |--------------------+--------------------+--------------------|
 |  1     4     28    |  9     367   2367  |  5     678   678   |
 |  9     6     5     |  147   8     47    |  2     3     147   |
 |  7     3     28    |  145   46    2456  |  9     468   1468  |
 |--------------------+--------------------+--------------------|
 |  4     2     9     |  6     1     78    |  3     5     78    |
 |  8     1     3     |  457   2     457   |  67    9     467   |
 |  6     5     7     |  348   9     348   |  1     48    2     |
 +--------------------------------------------------------------+
 # 55 eliminations remain

(4=7)r5c6 - r7c6 = r7c9 - (67=4)r8c7+9  =>  r5c9,r8c6<>4

 <68+7>  XYZ-Wing r4c9/r4c8+r7c9         <> 7    r5c9
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