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Puzzle 11/07/09: ~ XY

 
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sat Jul 09, 2011 9:55 pm    Post subject: Puzzle 11/07/09: ~ XY Reply with quote

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

Play this puzzle online at the Daily Sudoku site
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peterj



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

PostPosted: Sun Jul 10, 2011 8:28 am    Post subject: Reply with quote

Without going "extreme" this one didn't give in easy (for me)!
Quote:
w-wing(28) (2=8)r2c3 - r2c6=r8c6 - (8=2)r8c7 ; r2c7<>2
remote-pair(48) r7c1, r1c1, r3c2, r3c8 ; r7c8<>48
x-wing(8) r3, r6 ; r79c2<>8, r15c8<>8
xy-wing(28-5) r8c7 ; r5c8<>5

Danny, also let me echo Ted's comments - thanks for the puzzles!
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tlanglet



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

PostPosted: Sun Jul 10, 2011 2:03 pm    Post subject: Reply with quote

Like Peter, I also tried more standard moves but could not resist the anp() third step.

#1: Flightless xy-wing with pseudocell pincer plus transport; r1c1<>2
(2)r1c8=(2)r12c7-r8c7=r8c5-(2=8)r9c5-r8c6=r2c6-(8=2)r2c3;

#2: RP (48)r7c1=>r3c8; r7c8<>48

Code:
*-----------------------------------------------------------*
 | 48    7     1     | 9     38    6     | 2458  2458  358   |
 | 9     6     2     | 5     4     38    | 78    1     378   |
 | 3     48    5     | 7     1     2     | 9     48    6     |
 |-------------------+-------------------+-------------------|
 | 7     3     4     | 8     5     9     | 1     6     2     |
 | 2     1     89    | 3     6     4     | 578   589   578   |
 | 5     89    6     | 2     7     1     | 3     89    4     |
 |-------------------+-------------------+-------------------|
 | 48    2489  3     | 1     289   7     | 6     25    58    |
 | 6     5     89    | 4     2389  38    | 28    7     1     |
 | 1     248   7     | 6     28    5     | 248   3     9     |
 *-----------------------------------------------------------*

#3: Two options:
either
anp(89=5)r65c8*-(5=2)r7c8-(2=8)r8c7-r8c3=(8)r5c3 => r5c79<>58=7; invalid result thus r5c8<>5
(As always, any suggestions on a better/proper description of this step is appreciated.)

or
anp(5=78)r5c79-(8)r5c3=r8c3-(8=2)r8c7-(2=5)r7c8; r5c8<>5

Ted
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daj95376



Joined: 23 Aug 2008
Posts: 3855

PostPosted: Sun Jul 10, 2011 4:02 pm    Post subject: Reply with quote

tlanglet wrote:
Code:
*-----------------------------------------------------------*
 | 48    7     1     | 9     38    6     | 2458  2458  358   |
 | 9     6     2     | 5     4     38    | 78    1     378   |
 | 3     48    5     | 7     1     2     | 9     48    6     |
 |-------------------+-------------------+-------------------|
 | 7     3     4     | 8     5     9     | 1     6     2     |
 | 2     1     89    | 3     6     4     | 578   589   578   |
 | 5     89    6     | 2     7     1     | 3     89    4     |
 |-------------------+-------------------+-------------------|
 | 48    2489  3     | 1     289   7     | 6     25    58    |
 | 6     5     89    | 4     2389  38    | 28    7     1     |
 | 1     248   7     | 6     28    5     | 248   3     9     |
 *-----------------------------------------------------------*


anp(89=5)r65c8*-(5=2)r7c8-(2=8)r8c7-r8c3=(8)r5c3 => r5c79<>58=7; invalid result thus r5c8<>5
(As always, any suggestions on a better/proper description of this step is appreciated.)

Ted, I'd use:

Code:
(5=2)r7c8-(2=8)r8c7-r8c3=r5c3-r5c789=(8-9)r6c8=(9)r5c8  =>  r5c8<>5

If there had been a <5> in r6c8 as well, then I'd use =(8-9)r6c8* and deduce r56c8<>5.

Regards, Danny
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ronk



Joined: 07 May 2006
Posts: 397

PostPosted: Sun Jul 10, 2011 4:51 pm    Post subject: Reply with quote

tlanglet wrote:
#3: Two options:
either
anp(89=5)r65c8*-(5=2)r7c8-(2=8)r8c7-r8c3=(8)r5c3 => r5c79<>58=7; invalid result thus r5c8<>5
(As always, any suggestions on a better/proper description of this step is appreciated.)

or
anp(5=78)r5c79-(8)r5c3=r8c3-(8=2)r8c7-(2=5)r7c8; r5c8<>5

Or do both with an ALS (anp) on each end of one chain.

(57=8)r5c79 - (8)r5c3 = (8)r8c3 - (8=2)r8c7 - (2=5)r7c8 - (5=89)r56c8 ==> r5c79<>8, r56c8<>5 potentially
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tlanglet



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

PostPosted: Sun Jul 10, 2011 7:23 pm    Post subject: Reply with quote

Danny, I played around with various possibilities including the first portion of your suggested chain. I simply missed the obvious two final steps, marked in red.

(5=2)r7c8-(2=8)r8c7-r8c3=r5c3-r5c789=(8-9)r6c8=(9)r5c8 => r5c8<>5


Ron, I like your suggestion also. Once I have found a path, I often fail to seek another variation, such as your use of (57=8) rather than my (5=78). Hopefully I will get better in a few more years......

Thanks to both of you,

Ted
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susume



Joined: 13 May 2011
Posts: 36
Location: Southeastern US

PostPosted: Tue Jul 12, 2011 10:20 pm    Post subject: Reply with quote

A different ANP approach:

(4)r3c8=r3c2-r1c1=(4)r7c1 => r7c8<>4, r9c7=4
W wing (2=8)r2c3-r2c6=r8c6-(8=2)r8c7 => r3c7<>2
anp (38=5)r1c59-(5=8)r7c9-(8=2)r8c7-r12c7=(2-4)r1c8=(4)r1c1 => r1c18<>8
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Marty R.



Joined: 12 Feb 2006
Posts: 5061
Location: Rochester, NY, USA

PostPosted: Wed Jul 13, 2011 4:42 am    Post subject: Reply with quote

W-Wing (28), SL8 in c6; r2c7<>2
Kite; r1c7<>4
X-Wing; r1c8, r5c8, r7c28, r9c2<>8
BUG+2
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