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Oct 6 VH

 
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sdq_pete



Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL

PostPosted: Sat Oct 06, 2007 11:59 am    Post subject: Oct 6 VH Reply with quote

May I be the first? A quicker one - a remote pair (39) at this position finishes it off:

Code:

+---------+----------------+-------------+
| 37 8  6 | 1239  123 5    | 39 137 4    |
| 37 12 4 | 12389 6   2389 | 5  137 2379 |
| 5  12 9 | 123   7   4    | 8  6   23   |
+---------+----------------+-------------+
| 8  7  5 | 6     23  239  | 39 4   1    |
| 1  4  2 | 39    5   7    | 6  8   39   |
| 9  6  3 | 4     8   1    | 2  57  57   |
+---------+----------------+-------------+
| 4  3  1 | 5     9   6    | 7  2   8    |
| 26 9  7 | 1238  123 238  | 4  35  356  |
| 26 5  8 | 7     4   23   | 1  9   36   |
+---------+----------------+-------------+

Play this puzzle online at the Daily Sudoku site

Peter


Last edited by sdq_pete on Sat Oct 06, 2007 2:29 pm; edited 1 time in total
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Sat Oct 06, 2007 12:12 pm    Post subject: Reply with quote

Before you guys come out with your wings and things I want to show you my Empty Rectangle.

Looking at Pete's grid, there are only two 9s in R5. If the left one is the 9 obviously R1C4 is not a 9. If the right one is the 9 there is an L shaped hinge in Box 3 that also takes out the 9 in R1C4. This leaves a naked 9 in R1C7. Then "Bob's your uncle" - it's all over!


Last edited by cgordon on Sat Oct 06, 2007 12:40 pm; edited 1 time in total
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TKiel



Joined: 22 Feb 2006
Posts: 292
Location: Kalamazoo, MI

PostPosted: Sat Oct 06, 2007 12:49 pm    Post subject: Reply with quote

Perhaps the slowest way is to get it down to this BUG+1 position

Code:

 *--------------------------------------------------*
 | 7    8    6    | 29   23   5    | 39   1    4    |
 | 3    12   4    | 189  6    89   | 5    7    29   |
 | 5    12   9    | 13   7    4    | 8    6    23   |
 |----------------+----------------+----------------|
 | 8    7    5    | 6    23   29   | 39   4    1    |
 | 1    4    2    | 39   5    7    | 6    8    39   |
 | 9    6    3    | 4    8    1    | 2    5    7    |
 |----------------+----------------+----------------|
 | 4    3    1    | 5    9    6    | 7    2    8    |
 | 6    9    7    | 28   1    28   | 4    3    5    |
 | 2    5    8    | 7    4    3    | 1    9    6    |
 *--------------------------------------------------*


with the remote pair and ER/hinge move both still around, plus about 40 possibilities for a coloring exclusion. Seems that the <9> in r1c4 is the fatal exclusion.
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Earl



Joined: 30 May 2007
Posts: 677
Location: Victoria, KS

PostPosted: Sat Oct 06, 2007 2:13 pm    Post subject: Oct 6 VH Reply with quote

I'm old fashioned.
An x-wing (-3's) and a skyscraper (-9) and its done.

Earl
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Sat Oct 06, 2007 2:57 pm    Post subject: Reply with quote

I guess that makes me old fashioned, too. Did the xwing (r3,5 to be exact) on 3, then an elimination of 9 in r1c4 which is what I think Earl did but I would not have called this a skyscraper, rather a w-wing in this case, since two "39" cells (r1c6 and r5c4) connected by strong links via r4c6 and r5c9 eliminate all 3s and 9s they both see.This is what it loos like:
Code:

-9....39
 .     |
 .     |
 .     |
 .    39
 .      \
39------39


Edit: oops and I just realized this is exactly what Tracy already posted.

... and cgordon

... and Peter

well, sorry, a little slow in understanding today. Or is it the completely different terminology for one and the same thing?
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Sat Oct 06, 2007 3:25 pm    Post subject: Reply with quote

Actually after taking a second look at the available 9s, I see more skyscrapers here than in Manhattan. C69, C67, R14, R15 - to name a few.
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Marty R.



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

PostPosted: Sat Oct 06, 2007 3:25 pm    Post subject: Reply with quote

I started out with remote pairs on 39 (which I don't know was needed) and a W-Wing on 12 finished it off.
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Johan



Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium

PostPosted: Sat Oct 06, 2007 7:21 pm    Post subject: Reply with quote

An X-wing on <3> and an XY-wing with pivot in R2C6, eliminating <2> in R8C4, finished the puzzle for me.
But there was also a WXYZ-wing present in the grid, before finding the X-wing.
The WXYZ-wing pivot is in R2C9, eliminating the common Z number <3> in R2C8, though it didn't crack the puzzle, it's a very rare step to encounter in a VH puzzle.

This is the WXYZ-wing, w=2, x=9, y=7, z=3

Code:

+---------+--------------+-------------+
| 37 8  6 | 1239 123 5   |zx39 137 4   |
|zy37 12 4|1389 6   389  | 5  1-37*2379|
| 5  12 9 | 13   7   4   | 8  6  wz23  |
+---------+--------------+-------------+
| 8  7  5 | 6    23  239 | 39 4   1    |
| 1  4  2 | 39   5   7   | 6  8   39   |
| 9  6  3 | 4    8   1   | 2  57  57   |
+---------+--------------+-------------+
| 4  3  1 | 5    9   6   | 7  2   8    |
| 26 9  7 | 1238 123 238 | 4  35  356  |
| 26 5  8 | 7    4   23  | 1  9   36   |
+---------+--------------+-------------+
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