Ask for some patterns that they don't have puzzles.

Everything about Sudoku that doesn't fit in one of the other sections

Re: Mission impossible?

Postby udosuk » Tue Jun 05, 2007 1:43 pm

claudiarabia wrote:
Code: Select all
. . . x . x . . .
. x . . x . . x .
. . . x . x . . .
x . x . x . x . x
. x . x . x . x .
x . x . x . x . x
. . . x . x . . .
. x . . x . . x .
. . . x . x . . .

The corner boxes left with one number in the middle.

Your pattern is equivalent to this:
Code: Select all
. x . x . x x . x
x . x . x . . x .
. x . x . x x . x
x . x . . . . . .
. x . . x . . x .
x . x . . . . . .
x . x . . . . . .
. x . . x . . x .
x . x . . . . . .

Where 2 corner boxes have 5 clues and 1 has 4 clues.:idea:
udosuk
 
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Postby JPF » Tue Jun 05, 2007 8:32 pm

This sub-pattern is valid as well :

Code: Select all
 . . . | 1 . 2 | . . .
 . 3 . | . 4 . | . 1 .
 . . . | 5 . 6 | . . .
-------+-------+-------
 4 . 5 | . . . | 7 . 6
 . 8 . | . . . | . 4 .
 2 . 6 | . . . | 3 . 9
-------+-------+-------
 . . . | 9 . 5 | . . .
 . 2 . | . 8 . | . 7 .
 . . . | 2 . 3 | . . .

SE=8.4
24 clues, minimal

JPF
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Postby claudiarabia » Fri Jun 15, 2007 7:10 pm

Hi,

what about this pattern?

Code: Select all
x . x . x . x . x
. x . x . x . x .
x . x . x . x . x
. . . . . . . . .
. x . . x . . x .
. . . . . . . . .
x . x . x . x . x
. x . x . x . x .
x . x . x . x . x


I wouldn't mind when you need more clues in the rows 1-3 7-9:)
claudiarabia
 
Posts: 288
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Postby JPF » Fri Jun 15, 2007 8:26 pm

This pattern has obviously 2n solutions.
Here's an example with 2 solutions :

Code: Select all
 1 . 2 | . 3 . | 4 . 5
 . 6 . | 7 . 1 | . 8 .
 8 . 9 | . 2 . | 7 . 1
-------+-------+-------
 . . . | . . . | . . .
 . 3 . | . 4 . | . 2 .
 . . . | . . . | . . .
-------+-------+-------
 5 . 6 | . 8 . | 3 . 7
 . 1 . | 4 . 3 | . 5 .
 3 . 4 | . 6 . | 8 . 9


[Edit]
For the fun , here's one with 1000 solutions:)
Code: Select all
 1 . 2 | . 3 . | 4 . 5
 . 3 . | 6 . 5 | . 1 .
 5 . 7 | . 4 . | 8 . 3
-------+-------+-------
 . . . | . . . | . . .
 . 8 . | . 1 . | . 4 .
 . . . | . . . | . . .
-------+-------+-------
 8 . 4 | . 5 . | 3 . 6
 . 5 . | 4 . 6 | . 7 .
 6 . 1 | . 7 . | 9 . 4

[End Edit]

JPF
Last edited by JPF on Sat Jun 16, 2007 10:27 am, edited 1 time in total.
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Postby udosuk » Sat Jun 16, 2007 5:57 am

JPF wrote:This pattern has obviously 2n solutions.

In case Claudia still doesn't see it, you can freely swap r4 & r6 in any solution. Therefore this pattern cannot give a unique solution.
udosuk
 
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Postby Eioru » Tue Jun 19, 2007 9:12 am

How about this one.
Code: Select all
x.x.....x
.x..x....
x.x...x..
...x.x...
.x..x..x.
...x.x...
..x...x.x
....x..x.
x.....x.x


Original:
Code: Select all
AAA......
AAA......
AAA......
...AAA...
...AAA...
...AAA...
......AAA
......AAA
......AAA

Code: Select all
When there is 3 clues added, how many A can be taken?
  ...         4    ...     ,            ...         ?
  ...         5    ...     ,            ...         ?
  ...         6    ...     ,            ...         ?
Eioru
 
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Postby JPF » Tue Jun 19, 2007 9:38 am

The first pattern is easy ; you can even remove r5c5 :

Code: Select all
 1 . 2 | . . . | . . 3
 . 4 . | . 5 . | . . .
 3 . 6 | . . . | . . .
-------+-------+-------
 . . . | 1 . 7 | . . .
 . 6 . | . . . | . 4 .
 . . . | 3 . 2 | . . .
-------+-------+-------
 . . . | . . . | 3 . 2
 . . . | . 8 . | . 6 .
 9 . . | . . . | 4 . 7


JPF
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Postby m_b_metcalf » Tue Jun 19, 2007 1:23 pm

Eioru wrote:Original:
Code: Select all
AAA......
AAA......
AAA......
...AAA...
...AAA...
...AAA...
......AAA
......AAA
......AAA

Code: Select all
When there is 3 clues added, how many A can be taken?
  ...         4    ...     ,            ...         ?
  ...         5    ...     ,            ...         ?
  ...         6    ...     ,            ...         ?

Here are some quick results that set lower bounds not necessarily limits:
Code: Select all
 6 . . . . . 4 . .
 . . . . . . . 1 .
 . . . . . 8 . 5 3
 . . . . 4 1 6 . .
 . . . . 5 . . . .
 . . 3 . . 9 . . .
 1 7 8 3 . . . . .
 9 . . . . . . . .
 4 6 . . . . . . 5  With 6 added, remove 13
[Edit: Spurred on by JPF, we improve by 2.]
Code: Select all
 . . . . . . 6 8 5
 . . . . . . . 4 1
 . . . . . 2 . . .
 . . . . 3 . 8 . .
 . . . 1 5 9 . . .
 . . 6 . 7 . . . .
 8 . . 4 . . . . .
 2 3 7 . . . . . .
 . 5 1 . . . . . 7   With 5 added, remove 11
[Edit: Spurred on by JPF, we improve by 2.]
Code: Select all
 . . . . . . 2 1 4
 . . . . . . . . 6
 . . . . . 8 . 5 9
 . . . 6 . 5 3 . .
 . . . 3 9 4 . . .
 . . 2 1 . . . . .
 8 6 . 5 . . . . .
 3 . . . . . . . .
 4 1 7 . . . . . .  With 4 added, remove 9
 [Edit: Further improvement, by 1.]

Of course, putting the added cells in different positions could well change the results, as would any requirement to maintain symmetry.

Regards,

Mike Metcalf
Last edited by m_b_metcalf on Tue Jun 19, 2007 3:41 pm, edited 3 times in total.
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Postby JPF » Tue Jun 19, 2007 3:55 pm

14+6=20 :
Code: Select all
 
 
 1 . . | . . . | . . .
 2 . . | . 3 . | . 4 .
 . 5 6 | . . . | . . .
-------+-------+-------
 . . . | 7 . . | . . .
 . 7 . | 8 6 . | . . 5
 . . . | . 4 5 | . . .
-------+-------+-------
 . . . | . . . | . . 7
 4 . . | . 2 . | . . 6
 . . . | . . . | 5 1 8



13+6=19 :
Code: Select all
 1 . 2 | . . . | . . .
 . . . | . 3 . | . . .
 4 . 5 | . . . | . 1 .
-------+-------+-------
 . . . | 5 . 1 | . . 2
 . 6 . | . . . | . . .
 . . . | 7 . 8 | . . .
-------+-------+-------
 . . . | . . . | 5 . 3
 . . . | . . . | . 7 .
 . 9 . | . 2 . | 4 . 6



14+5=19 :
Code: Select all
 
 
 1 . . | . . . | . . .
 2 . . | . 3 . | . . .
 4 5 6 | . . . | . . .
-------+-------+-------
 . . . | 4 . . | . . .
 . 7 . | 5 . . | . 8 .
 . . . | 6 2 1 | . . .
-------+-------+-------
 . . . | . . . | 6 . .
 . 3 . | . 8 . | . . .
 . . . | . . . | 4 9 2



13+5=18 :
Code: Select all
 
 
 1 . . | . . . | . . .
 2 . . | . 3 . | . . .
 4 5 6 | . . . | . . .
-------+-------+-------
 . . . | 4 . . | . . .
 . 7 . | 5 . . | . 3 .
 . . . | 6 . 1 | . . .
-------+-------+-------
 . . . | . . . | 6 . .
 . 3 . | . 8 . | . . .
 . . . | . . . | 4 5 9

 

JPF
Last edited by JPF on Wed Jun 20, 2007 4:04 am, edited 2 times in total.
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Postby JPF » Tue Jun 19, 2007 6:37 pm

17+4=21 :
Code: Select all
 
 
 1 . . | . . . | . . .
 2 3 . | . 4 . | . . .
 5 6 7 | . . . | . . .
-------+-------+-------
 . . . | 5 . . | . . .
 . . . | 7 8 . | . 4 .
 . 5 . | 3 2 6 | . . .
-------+-------+-------
 . . . | . . . | 5 . .
 . . 9 | . . . | . 8 .
 . . . | . . . | 6 7 1
 


19+3=22 :
Code: Select all
 
 
 1 2 3 | . . . | . . .
 4 5 6 | . . . | . . .
 7 . . | . . . | . . .
-------+-------+-------
 . . . | 1 . 4 | . 7 .
 . 8 . | 2 . . | . . .
 . . . | 7 6 5 | . . .
-------+-------+-------
 . . . | . . . | 4 . .
 . . . | . 3 . | 6 . 9
 . . . | . . . | 1 2 5
 

JPF
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Postby Eioru » Mon Jun 25, 2007 8:38 pm

Original / Example1 / Example2 / Unknown
Code: Select all
**.....**     .*.....*.     .*.....**     **.....**
**.....**     **.....**     *......**     **.....**
....*....     ....*....     ....*....     ....*....
...*.*...     ...*.*...     ...*.*...     .....*...
..*...*..     ..*...*..     ..*...*..     ..*...*..
...*.*...     ...*.*...     ...*.*...     ...*.....
....*....     ....*....     ....*....     ....*....
**.....**     **.....**     **......*     **.....**
**.....**     .*.....*.     **.....*.     **.....**


Take any four or more clues from four corners of original pattern.
I think they might be difficult to find and have more Pointing with ER rating.
Last patten, which only has 6 pattern in the middle, I don't have seen yet.
Eioru
 
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Joined: 16 August 2006

Postby JPF » Mon Jun 25, 2007 10:14 pm

Eioru wrote:Last patten, which only has 6 pattern in the middle, I don't have seen yet.

Code: Select all
 1 2 . . . . . 3 4
 3 5 . . . . . 6 2
 . . . . 7 . . . .
 . . . . . 4 . . .
 . . 3 . . . 8 . .
 . . . 2 . . . . .
 . . . . 5 . . . .
 7 6 . . . . . 4 8
 5 4 . . . . . 9 7


The other patterns are easy.
For example :
Code: Select all
 . 1 . . . . . 2 3
 4 . . . . . . 5 6
 . . . . 5 . . . .
 . . . 3 . 2 . . .
 . . 4 . . . 7 . .
 . . . 1 . 8 . . .
 . . . . 6 . . . .
 9 3 . . . . . . 4
 5 2 . . . . . 3 .

SE=7.2

JPF
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Postby Mauricio » Mon Jun 25, 2007 10:59 pm

Impressive work!, JPF
The remaining pattern:
Code: Select all
 . 1 . . . . . 2 .
 2 3 . . . . . 4 1
 . . . . 5 . . . .
 . . . 1 . 6 . . .
 . . 7 . . . 8 . .
 . . . 4 . 3 . . .
 . . . . 9 . . . .
 9 4 . . . . . 1 7
 . 7 . . . . . 6 .    ER 8.8



BTW, I tried to create a sudoku with 19 clues or less and horizontal+vertical symmetry, unsuccesfully. Can anyone help me?
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Joined: 22 March 2006

Postby claudiarabia » Tue Jun 26, 2007 1:52 pm

Mauricio wrote:Impressive work!, JPF
The remaining pattern:
Code: Select all
 . 1 . . . . . 2 .
 2 3 . . . . . 4 1
 . . . . 5 . . . .
 . . . 1 . 6 . . .
 . . 7 . . . 8 . .
 . . . 4 . 3 . . .
 . . . . 9 . . . .
 9 4 . . . . . 1 7
 . 7 . . . . . 6 .    ER 8.8



BTW, I tried to create a sudoku with 19 clues or less and horizontal+vertical symmetry, unsuccesfully. Can anyone help me?


An outstanding sudoku. That is the first puzzle I see, the Explainer is using only advanced ramificated forcing chains to solve it. No ordinary forcing chain!

Claudia
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Postby claudiarabia » Tue Jun 26, 2007 2:01 pm

JPF wrote:This pattern has obviously 2n solutions.
Here's an example with 2 solutions :

Code: Select all
 1 . 2 | . 3 . | 4 . 5
 . 6 . | 7 . 1 | . 8 .
 8 . 9 | . 2 . | 7 . 1
-------+-------+-------
 . . . | . . . | . . .
 . 3 . | . 4 . | . 2 .
 . . . | . . . | . . .
-------+-------+-------
 5 . 6 | . 8 . | 3 . 7
 . 1 . | 4 . 3 | . 5 .
 3 . 4 | . 6 . | 8 . 9

...
[End Edit]

JPF

Finally I've seen it. A nice puzzle. I'm still unfamiliar with solving multisolutional sudokus. But I'm glad to find an unsolvable pattern for you.
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