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Free Press Mar 19, 2010

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Fri Mar 19, 2010 4:37 pm    Post subject: Free Press Mar 19, 2010 Reply with quote

This week, a VH:
Code:
Puzzle: FP031910
+-------+-------+-------+
| 8 . . | . . . | . . . |
| 6 . . | 3 1 9 | . . . |
| . . . | 5 . . | . 9 . |
+-------+-------+-------+
| 3 . 2 | . . . | 8 . . |
| . 9 . | 2 . 5 | . 7 . |
| . . 8 | . . . | . . 4 |
+-------+-------+-------+
| . 6 4 | . . 3 | . . . |
| . . . | 9 2 . | . . 7 |
| . . . | . . . | . . 5 |
+-------+-------+-------+
Keith
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Mogulmeister



Joined: 03 May 2007
Posts: 1151

PostPosted: Fri Mar 19, 2010 5:20 pm    Post subject: Reply with quote

Quote:
I went 3 steps:

1)A UR: r1c57 r3c57 a 6 in r1c7 would create a DP so it is gone leaving only 1 6 in column 7.

2)XY Chain: 1 is eliminated from r8c1 by pincers at r3c1 & r8c6

3)XY Chain: 6 eliminated pincers at r6c6 and r9c5.
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Fri Mar 19, 2010 7:11 pm    Post subject: Reply with quote

Quote:
(7=4)r4c6-r4c4=r1c4-(4=7)r3c57-r3c1=r6c1; r4c2,r6c6<>7 stte
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tlanglet



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

PostPosted: Fri Mar 19, 2010 7:43 pm    Post subject: Reply with quote

Two VH steps or one ALS move.

Quote:
xy-wing 1-57 with vertex in r3c1,
another xy-wing 1-47 with vertex again in r3c1, pincer 47 in r2c1 and the other pincer formed by extending the 1 in the vertex: (1)r3c1 - r6c1 = r6c4 - (1=4)r4c4; r1cc4<>4 to complete the puzzle.


A one step ALS 137 (or hidden pair 17) in r3c13 also completes the puzzle.
ALS[(7)r3c13 = (3)r3c3]r3c13 - r89c3 = r9c2 - (3=6)r9c8 - r8c8 = r8c6 - (6=7)r6c6 - (7=15)r68c1 - (1=7)r3c1; r1c2 | r2c3 | r3c257<>7.

Ted
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Fri Mar 19, 2010 7:49 pm    Post subject: Reply with quote

Two XY-wings will do it.
Keith
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Fri Mar 19, 2010 7:59 pm    Post subject: Reply with quote

tlanglet wrote:
Two VH steps or one ALS move.

xy-wing 1-57 with vertex in r3c1,
another xy-wing 1-47 with vertex again in r3c1, pincer 47 in r2c1 and the other pincer formed by extending the 1 in the vertex: (1)r3c1 - r6c1 = r6c4 - (1=4)r4c4; r1cc4<>4 to complete the puzzle.

Ted


Whats to extend?
Code:
+----------------+----------------+----------------+
| 8    47a  9    |-46   467  2    | 5    1    3    |
| 6    2    5    | 3    1    9    | 7    4    8    |
| 17   1347 137  | 5    47   8    | 6    9    2    |
+----------------+----------------+----------------+
| 3    17b  2    | 14c  9    47   | 8    5    6    |
| 4    9    6    | 2    8    5    | 3    7    1    |
| 17   5    8    | 16   3    67   | 9    2    4    |
+----------------+----------------+----------------+
| 2    6    4    | 7    5    3    | 1    8    9    |
| 5    8    13   | 9    2    16   | 4    36   7    |
| 9    137  137  | 8    46   146  | 2    36   5    |
+----------------+----------------+----------------+
Keith
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tlanglet



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

PostPosted: Fri Mar 19, 2010 8:59 pm    Post subject: Reply with quote

keith wrote:
tlanglet wrote:
Two VH steps or one ALS move.

xy-wing 1-57 with vertex in r3c1,
another xy-wing 1-47 with vertex again in r3c1, pincer 47 in r2c1 and the other pincer formed by extending the 1 in the vertex: (1)r3c1 - r6c1 = r6c4 - (1=4)r4c4; r1cc4<>4 to complete the puzzle.

Ted


Whats to extend?
Code:
+----------------+----------------+----------------+
| 8    47a  9    |-46   467  2    | 5    1    3    |
| 6    2    5    | 3    1    9    | 7    4    8    |
| 17   1347 137  | 5    47   8    | 6    9    2    |
+----------------+----------------+----------------+
| 3    17b  2    | 14c  9    47   | 8    5    6    |
| 4    9    6    | 2    8    5    | 3    7    1    |
| 17   5    8    | 16   3    67   | 9    2    4    |
+----------------+----------------+----------------+
| 2    6    4    | 7    5    3    | 1    8    9    |
| 5    8    13   | 9    2    16   | 4    36   7    |
| 9    137  137  | 8    46   146  | 2    36   5    |
+----------------+----------------+----------------+
Keith


Your xy-wing is straightforward; it does not need any transports.

However, I started searching for my second step in box 1 and noticed both the 47 in r1c2 and the 17 in r3c1 and then found the extended solution. I simply completed the puzzle before I had the occasion to spot you xy-wing; our search order was different.

Ted
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Marty R.



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

PostPosted: Fri Mar 19, 2010 10:22 pm    Post subject: Reply with quote

I used the 175 XY-Wing plus pincer transport. Either an XY-Wing (174) or five-cell XY-Chain removes the 4 from r2c4 to finish it off.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Fri Mar 19, 2010 11:33 pm    Post subject: Reply with quote

Ted,

At least for me, these rectangular XY-wings are very hard to spot.

Keith
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