Sudoku World Championship - 2007

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Sudoku World Championship - 2007

Postby Bigtone53 » Mon Apr 02, 2007 10:01 am

Congratulations to Thomas Snyder, a regular contributor to this Forum, for winning the 2007 World Sudoku Championship in Prague, having been runner-up last year.
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Postby coloin » Mon Apr 02, 2007 10:23 am

Yes Well done
I think he deserved to win it last year
He can sleep better now Im sure
:D
C
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Postby motris » Wed Apr 04, 2007 7:32 pm

Thanks for your kind words. My WSC trip report is now online at my blog if people want to know how it feels going through the championships. I also have two examples of a latin square puzzle, "tablecloth sudoku," that a teammate and I wrote while competing. More relevant for this forum is to post the playoff puzzle that determined the finals which was the diagonal sudoku that follows. Each of the playoff rounds had 2 puzzles and while the "final" puzzle was in the London Times, this tricky diagonal separated first from second place overall.

Image
Last edited by motris on Mon Feb 04, 2008 4:21 pm, edited 1 time in total.
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Postby wapati » Thu Apr 05, 2007 4:34 am

The final puzzle linked here:

http://wpc.puzzles.com/sudoku/jigsawFinals.htm

must be wrong.

First of all the puzzle is not unique without the extra information.

Worse, it is nor unique AFTER the extra information.


What was the real last puzzle?
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Postby Bigtone53 » Thu Apr 05, 2007 8:26 am

First of all the puzzle is not unique without the extra information.

Worse, it is nor unique AFTER the extra information.


I too thought that it did not have a unique solution, with interchangeable 3s, 6s and 9s. However, I had overlooked the condition that each jigsaw-shaped bit contains 1-9 and that sorted out the unique answer.
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Postby Pat » Thu Apr 05, 2007 8:29 am

wapati wrote:The final puzzle linked here:

http://wpc.puzzles.com/sudoku/jigsawFinals.htm

must be wrong.

First of all the puzzle is not unique without the extra information.

Worse, it is nor unique AFTER the extra information.


What was the real last puzzle?


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Postby udosuk » Thu Apr 05, 2007 6:45 pm

Thomas, finally solved both your tablecloth puzzles, tough challenges they are! Especially the 2nd one, spent ages mucking around with the candidates before a couple critical moves with the digit least useful at the start revealed some naked pairs... If you guys can solve these puzzles on pen & paper in several minutes then I know how far away I'm from your level...

Solution for puzzle 1 (UP)

Solution for puzzle 2

wapati, I found that the "jigsaw" puzzle does have a unique solution, even without the "extra information"! If you have doubts, post here or PM me 2 or more solutions you worked out, I'll tell you which one is correct.

And the X puzzle is also pretty tough if you do it on pen & paper... Here I'll post the text versions of the X puzzle and the jigsaw puzzle:
Code: Select all
WSC 2007 X puzzle
..2.1.7..
...7.8...
3.......1
.9.....6.
1.......5
.8.....4.
9.......8
...6.7...
..7.2.9..

WSC 2007 jigsaw puzzle
.5..2..3.
2....17.8
4.76.....
.....5...
52.....47
...7.....
.....35.4
3.65....1
.9..7..6.
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Postby wapati » Fri Apr 06, 2007 7:00 am

Pat wrote:
wapati wrote:The final puzzle linked here:

http://wpc.puzzles.com/sudoku/jigsawFinals.htm

must be wrong.

First of all the puzzle is not unique without the extra information.

Worse, it is nor unique AFTER the extra information.


What was the real last puzzle?




Yep, the added info does make it unique. Thanks!
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Postby udosuk » Sat Apr 07, 2007 2:49 am

wapati wrote:Yep, the added info does make it unique. Thanks!

Then again, without the added info it's still unique... But I think you don't care anymore...:)
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