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Puzzle 11/02/20 Difficult/Extreme

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daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Mon Feb 21, 2011 4:46 am Post subject: Puzzle 11/02/20 Difficult/Extreme

Code:

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

Play this puzzle online at the Daily Sudoku site

tlanglet

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

Posted: Mon Feb 21, 2011 3:39 pm Post subject:

Here is an "almost" naked pair (ANP) with an "almost" xy-chain. How is this properly described?

Code:

*-----------------------------------------------------------*
| 1 6 78 | 79 2 4 | 39 5 389 |
| 5 3 4 | 1 89 6 | 79 78 2 |
| 78 2 9 | 37 38 5 | 1 6 4 |
|-------------------+-------------------+-------------------|
|#289 #89 6-8 | 5 (34=9) 7 | 24 1 369 |
| 279 1 67 | 369 349 8 | 24 39 5 |
| 4 5 3 | 69 1 2 | 679 78 689 |
|-------------------+-------------------+-------------------|
| 3689 89 1 | 2 5 39 | 369 4 7 |
| 39 7 5 | 4 6 139 | 8 2 139 |
| 369 4 2 | 8 7 139 | 5 39 1369 |
*-----------------------------------------------------------*

The key is the 349 in r4c5; view it as r4c5=34 or r4c5=9
If r4c5=34 then: ANP(89=2)r4c12-(2=4)r4c7-(4=3)r4c5-(3=8)r3c5-r3c1=(8)r1c3; r4c3<>8
If r4c5=9 then: (9)r4c5-(9=8)r4c2; r4c3<>8

Comments..........

Ted

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Mon Feb 21, 2011 4:33 pm Post subject:

You could use a network notation:

Code:

ANP(89=2)r4c12-(2=4)r4c7-(4=3)r4c5-(3=8)r3c5-r3c1=(8)r1c3; r4c3<>8
||
-(4=9)r4c5-(9=8)r4c2; r4c3<>8

In the past, I would have used this network notation:

Code:

(4=3)r4c5-(3=8)r3c5-r3c1=(8)r1c3
/ \
ANP(89=2)r4c12-(2=4)r4c7- => r4c3<>8
\ /
(4=9)r4c5-(9=8)r4c2

peterj

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

Posted: Mon Feb 21, 2011 4:35 pm Post subject:

A simple wing - but with a killer transport!

Code:

xyz-wing(36-9) r5c4 transport -(9)r5c1=r4c12 ; r45c5<>9

Ted,

Quote:

The key is the 349 in r4c5

... as you say, isn't it really a kraken cell at heart?

Code:

kraken-cell(349) r4c5
(3)r4c5 - (3=8)r3c5 - r3c1=r1c3
||
(4)r4c5 - (4=2)r3c7 - (2=89)r3c12
||
(9)r4c5 - (9=8)r4c2

daj95376

Joined: 23 Aug 2008
Posts: 3854

Posted: Mon Feb 21, 2011 6:29 pm Post subject:

peterj wrote:

A simple wing - but with a killer transport!

Code:

xyz-wing(36-9) r5c4 transport -(9)r5c1=r4c12 ; r45c5<>9

Nice use of multiple eliminations along a chain. I tried to find a way of explicitly expressing it. However, I had to alter your logic a bit.

(9=6)r6c4 - (6=39)r5c48 - (9)r5c5,r5c1 = (9)r4c12; r4c5<>9

peterj

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

Posted: Mon Feb 21, 2011 6:51 pm Post subject:

daj95376 wrote:

I tried to find a way of explicitly expressing it.

Why not just?

Code:

(96=3)r65c4 - (3=9)r5c8* - r5c1=r4c12 ; *r5c5<>9, r4c5<>9

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Mon Feb 21, 2011 11:47 pm Post subject:

XY-Chain running from r2c5 to r4c2; r4c5<>9 XYZ-Wing (369); r5c5<>9

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