For the Sudoku crowd

[Eric Smith]

http://xkcd.com/c74.html

[Ed Look]

LOL!!

I've got to show this one to my kids!!

Good find!

[Eric Smith]

I'm still trying to come up with an optimal algorithm to solve it. I was going to use Alpha-Beta tree pruning, but I hear that Negascout is more efficient.

[Howard Owen]

I personally favor the "random drunk's walk over a cliff" algorithm to solve binary sudoku. You have to pass the output through an altitude filter to get bits out, but it's quite effective.

Regards,

Howard

[Etienne Victoria]

I just watched the World cup soccer game France vs. Brazil yesterday and got this Sudoku puzzle solved in 90 minutes (Sorry Luiz, Gerson & Nelson) :-)

Can anyone beat this ?

Etienne

Edited: 2 July 2006, 7:46 p.m. after one or more responses were posted

[Dave Shaffer (Arizona)]

"Can anyone beat this ?"

Assuming you are not talking about the soccer match (!), how about "unary" sudoku:

You have a single square, and you can put a zero in it (or not, if you need to think about it for a while).

[Gerson W. Barbosa]

Quote:

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(Sorry Luiz, Gerson & Nelson) :-)

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Hello Etienne,

I can't speak for Luiz & Nelson. Well, win some, lose some... as you say: c'est la vie...

Best regards from Brazil,

Gerson.

[Massimo Gnerucci (Italy)]

Quote:

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I just watched the World cup soccer game France vs. Brazil yesterday and got this Sudoku puzzle solved in 90 minutes (Sorry Luiz, Gerson & Nelson) :-)

Can anyone beat this ?

---

Yes, we just did it! 6-4 ;-)

Sorry dear french friends...

Greetings,
Massimo

[Etienne Victoria]

Congratulations!

There is a typo in your post: we're not "french friends" but "french fries" now ;-) because we're fried...

I think Italy definitely deserved to win, both for their global performance and for this last game!!

See you in the rugby tournament next year, in South Africa in 4 years....and in this forum within the next days!

I think I have to say...Forza Italia!

Best

Etienne

Edited: 9 July 2006, 6:06 p.m.

[Massimo Gnerucci (Italy)]

Hello Etienne,

Quote:

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I think Italy definitely deserved to win, both for their global performance and for this last game!!

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Well, you're a real sportsman! Chapeau!

Quote:

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See you in the rugby tournament next year,

---

Ouch!

Quote:

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I think I have to say...Forza Italia!

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Well, not really... this slogan was robbed by a political party...

Greetings,
Massimo

[Etienne Victoria]

Oooops sorry!

I forgot this aspect...I thought it just meant "Powerful Italy".

Etienne

Edited: 10 July 2006, 6:46 a.m. after one or more responses were posted

[Frank Wales]

Bar Italia in London was festooned with 'Forza Azzuro' banners a couple of weeks ago, and they were giving out free whistles to a crowd outside in what seemed like a contest of volume with the Italian restaurant next door. Thankfully, the noise didn't spoil the taste of the coffee.

I can't imagine how loud they would have been on Sunday night, though.

[Gerson W. Barbosa]

Ciao Massimo,

Congratulazioni Tetracampeoni!

Qui a casa mia abbiamo tutti fatto il tifo per l'Azzurra. Stasera mangieremo una bella pizza. Ne ho già ordinato una in Pizzeria Baggio. Nessuna intenzione di ricordare USA '94: Baggio è soltanto la mia pizzeria preferita :-)

Gerson

---------------

Here we have supported Squadra Azzura (sorry Les Bleus!). I've just ordered a Pizza from Baggio Pizzeria (nothing to do with the USA '94 Final: Baggio just happens to be my preferred pizzeria :-)

[Etienne Victoria]

Well... I must confess I also ate pizza & gelati...

Cheers.

Etienne

[Gerson W. Barbosa]

Hello Etienne,

It seems you're a good sport!

Congratulations to France. Being number 2 is also nice. Congratulations to Germany and Portugal as well (Not always winning is not that bad. Losing without a fight is pretty worse...).

Best regards,

Gerson.

[Etienne Victoria]

Hello Gerson,

I love Italy! Just walking in the streets of Bologna is a delight for me.

It's a pleasure to compete friendly with the people that built such a country.

But my favorite Italian is definitely a beautiful lady - and also Hp calculator addict!

She even has her own website here.

Greetings to Brazil!

Etienne

[Paul Dale]

Come one everyone, the problem as stated is over specified. I can halve the number of solved squares and the problem is still tractable :-)

[ECL]

I noticed on the 'About' page: http://xkcd.com/about.html that Randall is working at the same NASA center that I'm currently at. Perhaps I'll say hello.

On a side note, most of the fellows I work with still use HPs. Mostly 48GXs'.

ECL

[Paul Brogger]

Has anyone put up any base-16 Sudoku?

   + - - - - + - - - - + - - - - + - - - - +

   | 1       |   9   3 |     5   |   E     |

   |     2   |         |   6     |     F   |

   |         | 4       |   B     |       D |

   |   7   8 |     A   |     C   | 0       |

   + - - - - + - - - - + - - - - + - - - - +

   |   9   3 |         |         |         |

   |         |         |         |         |

   |     A   |         |         |         |

   | 4       |         |         |         |

   + - - - - + - - - - + - - - - + - - - - +

   |     5   |         |         |         |

   |   B     |         |         |         |

   |   6     |         |         |         |

   |     C   |         |         |         |

   + - - - - + - - - - + - - - - + - - - - +

   | 0       |         |         |         |

   |       D |         |         |         |

   |   E     |         |         |         |

   |     F   |         |         |         |

   + - - - - + - - - - + - - - - + - - - - +

. . . etc.

[Howard Owen]

Um, how do you get a sudoku when you aren't dealing with a square number of digits? Remember that '0' doesn't appear in decimal sudoku.

I guess adding 0 for hexadecimal sudoku to get a 4x4 grid would be acceptable. But being picky (and mangling the nomenclature,) wouldn't heptadecimal (or heptadekimal, or septuadecimal) be the right base for a "four-square sudoku?"

Regards,
Howard

[Paul Brogger]

I think you just need nine symbols for a three-by-three puzzle, and they started with '1' rather than '0'.

For a four-by-four puzzle, one could use the sixteen symbols '1'-'G', or (more familiar to some programmers, at least) '0'-'F'.

I guess I'm not very picky . . .

Hey, Wikipedia has a good article, with variations. Look!

And another twist: how about three-by-three-by-three ("three cubed"?) Sudoku? (Might be hard to do on paper -- you'd need nine sheets and an ability to visualize the spatial relationships.)

Edited: 10 July 2006, 7:33 p.m.

[Frank Wales]

Quote:

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Has anyone put up any base-16 Sudoku?

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They certainly have; the Daily Mail's been doing them
for months, but they just call them "Horrific Sudoku".

Here's today's.

Many more here.

[Valentin Albillo]

Have a look at this very interesting link (includes further references):

Sudoku Variations

Best regards from V.