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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Sat Aug 22, 2009 1:28 pm Post subject: Aug 22 DB |
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The August 22 DB offers x-wings, coloring, etc. but you need only this one step.
Solution: 23 W-wing
Earl
| Code: |
+-------+-------+-------+
| . . . | 7 . . | . 9 4 |
| 7 . 1 | 6 . . | . . . |
| . . 8 | . 1 4 | . . 7 |
+-------+-------+-------+
| 1 7 6 | 8 . . | . . . |
| . . . | . 5 . | . . . |
| . . . | . . 6 | 8 7 1 |
+-------+-------+-------+
| 6 . . | 9 7 . | 4 . . |
| . . . | . . 5 | 9 . 8 |
| 5 3 . | . . 1 | . . . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Aug 22, 2009 5:06 pm Post subject: |
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After basics: | Code: | +-------------+-------------+-------------+
| 23 6 5 | 7 23 8 | 1 9 4 |
| 7 4 1 | 6 239 29 | 5 8 23 |
| 239 29 8 | 5 1 4 |236* 26* 7 |
+-------------+-------------+-------------+
| 1 7 6 | 8 4 29 | 23 5 239 |
| 8 29 3 | 1 5 7 |-26* 4 -269*|
| 29 5 4 | 3 29 6 | 8 7 1 |
+-------------+-------------+-------------+
| 6 8 2 | 9 7 3 | 4 1 5 |
| 4 1 7 | 2 6 5 | 9 3 8 |
| 5 3 9 | 4 8 1 | 7 26* 26* |
+-------------+-------------+-------------+ |
There is a possible DP <26> in R359.
Either R3C7 is <3> or R5C9 is <9>. Either way, R5C79 are not <2>, and the puzzle is solved.
Keith  |
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dlnichols
Joined: 22 Aug 2009
Posts: 2
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| Posted: Sat Aug 22, 2009 5:14 pm Post subject: August 22 ???? |
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| It appears to be a guess. Do you have a solution? |
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dlnichols
Joined: 22 Aug 2009
Posts: 2
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| Posted: Sat Aug 22, 2009 5:30 pm Post subject: what is a W-wing? |
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| What is a W-wing? |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Aug 22, 2009 9:59 pm Post subject: |
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dl,
Welcome to the forum!
If you are ready to try W-wings, please read this thread:
http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=2143
You will learn about general Remote Pairs, M-wings, etc.
The basic idea is that if you have two unconnected cells with the same two candidates, how can you connect them?
Best wishes,
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Aug 22, 2009 10:20 pm Post subject: |
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dl,
After basics:
| Code: | +-------------+-------------+-------------+
| 23 6 5 | 7 23 8 | 1 9 4 |
| 7 4 1 | 6 239 29# | 5 8 23@ |
| 239 29 8 | 5 1 4 | 236 26 7 |
+-------------+-------------+-------------+
| 1 7 6 | 8 4 29# | 23@ 5 2-39 |
| 8 29 3 | 1 5 7 | 26 4 269 |
| 29 5 4 | 3 29 6 | 8 7 1 |
+-------------+-------------+-------------+
| 6 8 2 | 9 7 3 | 4 1 5 |
| 4 1 7 | 2 6 5 | 9 3 8 |
| 5 3 9 | 4 8 1 | 7 26 26 |
+-------------+-------------+-------------+ |
Notice the pair <23> labeled @. How can they be connected? Well, there is a strong link on <2> labeled #.
The logic is: One of the # cells must be <2>, so one of the @ cells must be <3>. So, R4C9 cannot be <3>, solving the puzzle with only further basic moves.
Best wishes,
Keith |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Aug 22, 2009 10:30 pm Post subject: Re: August 22 ???? |
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| dlnichols wrote: | | It appears to be a guess. Do you have a solution? |
dl,
If you mean my previous message on a Deadly Pattern, this is not a guess:
If all of the cells marked * have only possibilities <26>, the puzzle does not have a unique solution. You can exchange 2 for 6 in any of the * cells, and still have a valid solution.
To break up the <26> Deadly Pattern, | Quote: |
Either R3C7 is <3> or R5C9 is <9>. Either way, R5C79 are not <2>, and the puzzle is solved. |
Is this good stuff, or not! 
Keith |
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strmckr
Joined: 18 Aug 2009
Posts: 66
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| Posted: Sun Aug 23, 2009 7:20 am Post subject: |
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| Code: | *--------------------------------------------------*
| 23 6 5 | 7 23 8 | 1 9 4 |
| 7 4 1 | 6 39 29 | 5 8 23 |
| 39 29@ 8 | 5 1 4 | 23-6 26@ 7 |
|----------------+----------------+----------------|
| 1 7 6 | 8 4 29 | 23 5 239 |
| 8 29@ 3 | 1 5 7 | 26@ 4 69 |
| 29 5 4 | 3 29 6 | 8 7 1 |
|----------------+----------------+----------------|
| 6 8 2 | 9 7 3 | 4 1 5 |
| 4 1 7 | 2 6 5 | 9 3 8 |
| 5 3 9 | 4 8 1 | 7 26 26 |
*--------------------------------------------------* |
W-Wing: 6/2 in r3c8,r5c7 connected by 2 in r35c2 => r3c7<>6
also works... |
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