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July 1 VH

 
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Earl



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

PostPosted: Wed Jul 01, 2009 1:58 am    Post subject: July 1 VH Reply with quote

You can do this the hard way with coloring and wings, or the easy way.

Easy Solution: UR (86) eliminates 8 & 6 in R2C1 and solves the puzzle


Early Earl
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smegly



Joined: 19 Oct 2008
Posts: 4
Location: Texas

PostPosted: Wed Jul 01, 2009 5:39 am    Post subject: Reply with quote

Earl,

No coloring here, but it was kinda tough to bust this one. I saw the UR but didn't use that either. xy-wing did it for me if I recall, although and xyz was use one prior to that. Can't remember how it went but it left two equal bi-values in column six in the middle box. I'll have to write down the major moves from now on since I sure can't remember them by the time the puzzle is solved.

P.S. - Funny that you are in St. Louis. I'm up here visiting for a while.
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crunched



Joined: 05 Feb 2008
Posts: 168

PostPosted: Wed Jul 01, 2009 6:43 am    Post subject: Reply with quote

Looks like there are multiple wings and things in this puzzle:
An x wing on 4s removes several 4s. Then an xy wing: 23-27-37.
Puzzle after basics:

Code:

+--------------+--------------------+----------+
| 67   3   5   | 27    267    8     | 4 9  1   |
| 1678 178 9   | 4     1367   137   | 5 2  68  |
| 68   2   4   | 19    5      19    | 3 7  68  |
+--------------+--------------------+----------+
| 457  579 8   | 79    47     6     | 1 3  2   |
| 1347 179 137 | 12379 123478 13479 | 6 48 5   |
| 2    6   13  | 5     1348   134   | 7 48 9   |
+--------------+--------------------+----------+
| 137  4   2   | 6     9      137   | 8 5  37  |
| 58   58  6   | 37    347    2     | 9 1  347 |
| 9    17  137 | 8     1347   5     | 2 6  347 |
+--------------+--------------------+----------+

Play this puzzle online at the Daily Sudoku site
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themarsman



Joined: 17 Jun 2007
Posts: 7

PostPosted: Wed Jul 01, 2009 8:16 am    Post subject: Reply with quote

crunched wrote:
Looks like there are multiple wings and things in this puzzle:
An x wing on 4s removes several 4s. Then an xy wing: 23-27-37.
Puzzle after basics:

Code:

+--------------+--------------------+----------+
| 67   3   5   | 27    267    8     | 4 9  1   |
| 1678 178 9   | 4     1367   137   | 5 2  68  |
| 68   2   4   | 19    5      19    | 3 7  68  |
+--------------+--------------------+----------+
| 457  579 8   | 79    47     6     | 1 3  2   |
| 1347 179 137 | 12379 123478 13479 | 6 48 5   |
| 2    6   13  | 5     1348   134   | 7 48 9   |
+--------------+--------------------+----------+
| 137  4   2   | 6     9      137   | 8 5  37  |
| 58   58  6   | 37    347    2     | 9 1  347 |
| 9    17  137 | 8     1347   5     | 2 6  347 |
+--------------+--------------------+----------+

Play this puzzle online at the Daily Sudoku site


You still have simple eliminations that you didn't use. In box eight the fours are only in the center column so you can eliminate them from box five and solve a lot more of the puzzle. After that a simple XY wing solves it.
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Mike S



Joined: 15 May 2009
Posts: 6

PostPosted: Wed Jul 01, 2009 9:04 am    Post subject: Reply with quote

Code:

+--------------+--------------------+----------+
| 67   3   5   | 27    267    8     | 4 9  1   |
| 1678 178 9   | 4     1367   137   | 5 2  68  |
| 68   2   4   | 19    5      19    | 3 7  68  |
+--------------+--------------------+----------+
| 457  579 8   | 79    47     6     | 1 3  2   |
| 1347 179 137 | 12379 123478 13479 | 6 48 5   |
| 2    6   13  | 5     1348   134   | 7 48 9   |
+--------------+--------------------+----------+
| 137  4   2   | 6     9      137   | 8 5  37  |
| 58   58  6   | 37    347    2     | 9 1  347 |
| 9    17  137 | 8     1347   5     | 2 6  347 |
+--------------+--------------------+----------+


I'm very new to sudoku so, I may be way off about this.
In the above code there is 347 in row 8, cols 5 and 9.
There is 1347 in row 9 col 5 and 347 in row 9 col 9.
So, shouldn't that make row 9 col 5 a 1 because if it
isn't then this puzzle could have 3 solutions? Anyway,
I used that "logic" and solved the puzzle. Maybe I
just got lucky.
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arkietech



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

PostPosted: Wed Jul 01, 2009 12:40 pm    Post subject: Reply with quote

Fort those who do not like ur's there is:
Quote:
a xy-wing 723

that solves it.
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crunched



Joined: 05 Feb 2008
Posts: 168

PostPosted: Wed Jul 01, 2009 1:25 pm    Post subject: Reply with quote

themarsman wrote:

You still have simple eliminations that you didn't use. In box eight the fours are only in the center column so you can eliminate them from box five and solve a lot more of the puzzle. After that a simple XY wing solves it.


Ahhhh. You are right. The x-wings were not needed. Below is what I got after doing the eliminations themarsman points out: exposing the 2-3-7 xy wing.

Code:

+--------------+-------------+----------+
| 67   3   5   | 27 26   8   | 4 9  1   |
| 1678 178 9   | 4  36   37  | 5 2  68  |
| 68   2   4   | 1  5    9   | 3 7  68  |
+--------------+-------------+----------+
| 4    5   8   | 9  7    6   | 1 3  2   |
| 137  9   137 | 23 1238 134 | 6 48 5   |
| 2    6   13  | 5  138  134 | 7 48 9   |
+--------------+-------------+----------+
| 137  4   2   | 6  9    137 | 8 5  37  |
| 3578 78  6   | 37 34   2   | 9 1  347 |
| 9    17  137 | 8  134  5   | 2 6  347 |
+--------------+-------------+----------+

Play this puzzle online at the Daily Sudoku site
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ttsmurphy81



Joined: 26 May 2007
Posts: 11

PostPosted: Wed Jul 01, 2009 4:07 pm    Post subject: Reply with quote

Somehow I did this one with only simple eliminations in under 6 minutes. No advanced techniques at all.
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gindaani



Joined: 06 Mar 2009
Posts: 79

PostPosted: Wed Jul 01, 2009 4:33 pm    Post subject: Reply with quote

ttsmurphy81 wrote:
Somehow I did this one with only simple eliminations in under 6 minutes. No advanced techniques at all.

That happens to me sometimes too. I usually find I cannot repeat the process. Shocked
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keith



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

PostPosted: Wed Jul 01, 2009 11:39 pm    Post subject: Reply with quote

I had the same solution as "crunched".

I think the point is, take the "advanced" steps when they become apparent, not when you are sure no other basic steps are possible.

Keith
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gliebp



Joined: 29 Jun 2009
Posts: 1

PostPosted: Thu Jul 02, 2009 5:14 am    Post subject: Re: July 1 VH Reply with quote

Earl wrote:
You can do this the hard way with coloring and wings, or the easy way.

Easy Solution: UR (86) eliminates 8 & 6 in R2C1 and solves the puzzle


Early Earl
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Thu Jul 02, 2009 9:48 pm    Post subject: Reply with quote

Mike S wrote:
Code:

+--------------+--------------------+----------+
| 67   3   5   | 27    267    8     | 4 9  1   |
| 1678 178 9   | 4     1367   137   | 5 2  68  |
| 68   2   4   | 19    5      19    | 3 7  68  |
+--------------+--------------------+----------+
| 457  579 8   | 79    47     6     | 1 3  2   |
| 1347 179 137 | 12379 123478 13479 | 6 48 5   |
| 2    6   13  | 5     1348   134   | 7 48 9   |
+--------------+--------------------+----------+
| 137  4   2   | 6     9      137   | 8 5  37  |
| 58   58  6   | 37    347    2     | 9 1  347 |
| 9    17  137 | 8     1347   5     | 2 6  347 |
+--------------+--------------------+----------+


I'm very new to sudoku so, I may be way off about this.
In the above code there is 347 in row 8, cols 5 and 9.
There is 1347 in row 9 col 5 and 347 in row 9 col 9.
So, shouldn't that make row 9 col 5 a 1 because if it
isn't then this puzzle could have 3 solutions? Anyway,
I used that "logic" and solved the puzzle. Maybe I
just got lucky.

UR logic tells us that
Code:
12|12
-----
12|12

has two solutions

Code:
1|2
---
2|1

and
Code:
2|1
---
1|2
.

you are saying that this
Code:
347|347
-------
347|347

has three solutions?
hmm...
Code:

3|4   1
---
7|3


3|7  2
---
4|3


4|3  3
---
7|4 


4|7  4
---
3|4


7|3  5
---
4|7


7|4  6
---
3|7



in Wapati's thread,
http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=3731&sid=2a6b59a751cfd1b9fca786e2b2e7cd9d

his example provides your pattern where the logic wouldn't make sense.

Code:
.------------------.------------------.------------------.
| 7     4     29   | 25    6     1    | 8     3     59   |
| 1     5     269  | 3     79    8    | 279   4     679  |
| 8     69    3    | 25    4     79   | 279   1     5679 |
:------------------+------------------+------------------:
| 69    2     1    | 689   89    4    | 5     7     3    |
| 5     8     69   |*679   3    *679  | 4     2     1    |
| 3     7     4    | 1     2     5    | 6     9     8    |
:------------------+------------------+------------------:
| 2     3     8    |*679   1    *679  | 79    5     4    |
| 49    1     5    | 4789  789   2    | 3     6     79   |
| 469   69    7    | 49    5     3    | 1     8     2    |
'------------------'------------------'------------------'

in the marked cells above.
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keith



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

PostPosted: Fri Jul 03, 2009 12:51 am    Post subject: Reply with quote

Mike S:

You got lucky.

http://www.dailysudoku.com/sudoku/forums/viewtopic.php?t=3578

Keith
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