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nataraj
Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
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 Posted: Tue Feb 26, 2008 7:14 am Post subject: Feb 26 VH |
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Feels like I needed way too many steps for this one.
First, very early, I spotted an xy-wing (almost by accident) 68-18-16 that didn't solve too much.
Coloring on 5 eliminated a few candidates in box 9, which opened an xy-wing 25-12-15, which in turn opend another xy-wing 29-25-59, which finally solved the puzzle.
So many 25, 59 cells, I am sure there must be a w-wing and/or DPs around, too. |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Tue Feb 26, 2008 8:04 am Post subject: |
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The possible [25] UR* in R89C16 creates two pincer cells for digit <5>, that takes out both <5>'s in R7C78 and <5> in R9C6 solving the puzzle.
For avoiding the DP
either:
R9C1=9 => R9C5=1 => R9C7=5(B)
or:
R89C6=1=> R9C5=9 => R7C4=5(A)
| Code: | +--------------------------+--------------------------+--------------------------+
| 6 7 9 | 2 18 3 | 4 15 158 |
| 1 4 2 | 59 689 568 | 37 37 68 |
| 8 3 5 | 7 4 16 | 2 9 16 |
+--------------------------+--------------------------+--------------------------+
| 3 29 1 | 8 5 7 | 6 4 29 |
| 4 25 6 | 1 3 9 | 8 25 7 |
| 7 59 8 | 6 2 4 | 135 135 159 |
+--------------------------+--------------------------+--------------------------+
| 259 1 3 | 59 A 68 68 |-[5]7 2-[5]7 4 |
|*25 8 4 | 3 7 *125 | 9 6 125 |
|*259 6 7 | 4 19 *12-[5] | 15 B 8 3 |
+--------------------------+--------------------------+--------------------------+ |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Tue Feb 26, 2008 9:03 am Post subject: |
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I'll post again, but I'm sure this was a two stepper.
and I was reading over on the players forum that Ravel quit posting, is this correct?? hope not.
Norm |
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andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
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| Posted: Tue Feb 26, 2008 9:26 am Post subject: |
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Pretty straightforward, I thought; an xy on 1,5,9 broke it right open, making it a one-step job. 
John |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Tue Feb 26, 2008 1:14 pm Post subject: Feb 26 VH |
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I got this far and stared at it for some time till I saw a frequent solution to a VH - xy-wings: (125) and (159).
Earl
| Code: |
+----------+-----------+----------+
| 6 7 9 | 2 18 3 | 4 15 58 |
| 1 4 2 | 59 89 56 | 37 37 68 |
| 8 3 5 | 7 4 16 | 2 9 16 |
+----------+-----------+----------+
| 3 29 1 | 8 5 7 | 6 4 29 |
| 4 25 6 | 1 3 9 | 8 25 7 |
| 7 59 8 | 6 2 4 | 13 13 59 |
+----------+-----------+----------+
| 259 1 3 | 59 6 8 | 57 27 4 |
| 25 8 4 | 3 7 125 | 9 6 12 |
| 259 6 7 | 4 19 25 | 15 8 3 |
+----------+-----------+----------+
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Play this puzzle online at the Daily Sudoku site
I did the puzzle again and all I needed was a single xy-wing to make R7C7 = 7. How did I miss that the first time around.?
Last edited by Earl on Tue Feb 26, 2008 5:30 pm; edited 3 times in total |
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Mindwarp
Joined: 13 Sep 2007
Posts: 25
Location: St. Ives, England
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| Posted: Tue Feb 26, 2008 2:42 pm Post subject: |
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I guess I got lucky with this one I was able to solve it in under 7 minutes.  It makes a change! |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Tue Feb 26, 2008 4:39 pm Post subject: |
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| Could I have gotten lucky, or more accurately, unlucky? After writing in the candidates, the puzzle did not survive the initial scan, with constant erasing and cell-solving until it was done with nothing more than subsets and locked candidates. One thing I hate more than puzzles I can't solve is puzzles that solve too quickly when I'm looking forward to killing 30-40 minutes. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Tue Feb 26, 2008 6:58 pm Post subject: |
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| I like the xy-wing solution to this one |
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