The New Sudoku Players' Forum

[disraeli]

Our local paper is starting a daily sudoku next week. They printed the photo of the sky one puzzle as an example - stupid or what? Anyone who is new to sudoku and tried to do it will have given up very quickly in disgust, possibly never to get interested in sudoko again. When I rang the paper to tell them about their boob, with the suggestion they print something saying that this puzzle is a travesty of the real thing, they were not interested. If this is the standard of the new sky one programme I am tempted to give it a miss.

[RFB]

In fact, not only does it have nearly 2000 solutions, but there are a couple of other stupid things as well. It says "Simply print off the grid, and complete it and send it in".

1. If you print off the grid using the supplied Print button, all the squares are black, so unless you use a white pen, they are not going to show up.
2. It is called an 'Online competition', but you have to post your correct entry, you don't appear to be able to send it to an email address. Hardly 'online'.

Tabber

Where does it say 'send it in' - the only link I have seen in this thread is to the BBC news story

[Bernard Stay]

I complained to SkyOne about their puzzle and got the following reply:

Thank you for your email about Voderman's Sudoku Live.

I was sorry to read of your dissatisfaction with the above programme.

If you wish, you can submit an answer that you believe to be correct together with your method of working it out and we will be happy to look at it. You can forward it to Andrea Hamilton at the address listed below.

BSkyB
Unit 2
Grant Way
Isleworth
TW7 5QD

Please rest assured that, your comments have been noted and passed on to Sky One.

Thank you, for taking the time to contact us, and for your interest in Sky.

Kind regards

Angela Hart
Viewer Relations

-----Original Message-----

The giant Su Doku puzzle on the SkyOne site is a disgrace. It has hundreds of possible solutions and can't be solved by logical process.

The competition is an insult and pointless. An apology should be posted.

Bernard Stay

Anybody like to take them up on their invitation?

[jonallen1966]

well they have apologised now :

http://www.skyone.co.uk/programme/pgefeature.aspx?pid=48&fid=129

[scrose]

Well done Sudoku enthusiasts!

Rather than apologising for their poor puzzle-setting skills, they are congratulating us for pointing this out.

You've spotted that our record-breaking Sudoku grid has more than one solution.

More than one?! Bit of an understatement...

Seems like they haven't said anything more substantial than "my bad".

[Bernard Stay]

Perhaps if someone sent them a few hundred solutions (in condensed form somehow) it might give them cause for thought, if not a grovel. I can't, as I didn't manage even one solution, let alone 1905!

[simes]

I did post it here... but it took three posts to get it all in. A better idea will be to put on my web site, so it will be appearing here shortly.

[scrose]

If you wish, you can submit an answer that you believe to be correct together with your method of working it out and we will be happy to look at it.

As mentioned in the letter that Bernard Stay received, it appears that Sky One may require an explanation of how each solution is reached (even though I cannot find this requirement mentioned in their rules). To complement simes' excellent list of grids, I have provided a chain of reasoning for each of the 1905 solutions. Of course, all of this is moot since the contest closed yesterday.

[Bernard Stay]

Thanks S

I have mailed a sizeable chunk of these to Sky (though I doubt they will apologise).

[r.e.s.]

It's a shame that such a poorly constructed puzzle (no pun intended) is going to make its way into the Guinness World Records. It has 1905 unique [sic] solutions.

Code: Select all

 5 . 6 | . 2 . | 9 . 3
 . . 8 | . . . | 5 . .
 . . . | . . . | . . .
-------+-------+-------
 6 . . | 2 8 5 | . . 9
 . . . | 9 . 3 | . . .
 8 . . | 7 6 1 | . . 4
-------+-------+-------
 . . . | . . . | . . .
 . . 4 | . . . | 3 . .
 2 . 1 | . 5 . | 6 . 7

<"World's Largest Sudoku Puzzle">
What would be a simple way to repair the Sky One puzzle (to make it have a unique solution)?
Can it be done by changing just one of the given digits? Changing two? Must more be added?

[tarek]

Code: Select all

 5 . 6 | 4 2 . | 9 . 3 
 . . 8 | . . 7 | 5 . . 
 . . 7 | . . . | 4 . . 
-------+-------+------
 6 . . | 2 8 5 | . . 9 
 . . . | 9 . 3 | . . . 
 8 . . | 7 6 1 | . . 4 
-------+-------+------
 . . 9 | . . . | 1 . . 
 . . 4 | 6 . . | 3 . . 
 2 . 1 | . 5 4 | 6 . 7 

Tarek

[r.e.s.]

Tarek,
Actually, a unique solution can be forced by (symmetrically) adding only two digits, instead of your eight -- but I wonder if it can be done by changing only one or two of the givens. (By "changing" I mean giving a different digit in the same place.)

[ravel]

.. but I wonder if it can be done by changing only one or two of the givens.

No, i tried all combinations with up to 2 different digits - none unique.

[ravel]

Also changing 3 digits cannot not make it unique. This is a unique puzzle with 4 digits changed. It is easy to solve (needs pairs only). Shall we write a petition to change it (they could reuse a 3 and a 9) ?

Code: Select all

Old            New
------------   ------------
5.6|.2.|9.3    9.6|.2.|7.8
..8|...|5..    ..8|...|5..
...|...|...    ...|...|...
------------   ------------
6..|285|..9    6..|285|..9
...|9.3|...    ...|9.3|...
8..|761|..4    8..|761|..4
------------   ------------
...|...|...    ...|...|...
..4|...|3..    ..4|...|3..
2.1|.5.|6.7    2.3|.5.|6.7
------------   ------------


[r.e.s.]

Also changing 3 digits cannot not make it unique. This is a unique puzzle with 4 digits changed. It is easy to solve (needs pairs only).

Interesting ... If so many would need to be changed, I guess just adding two would be the simplest fix:

Code: Select all

 5 . 6 | . 2 . | 9 . 3 
 . . 8 | . . . | 5 . . 
[1]. . | . . . | . . . 
-------+-------+-------
 6 . . | 2 8 5 | . . 9 
 . . . | 9 . 3 | . . . 
 8 . . | 7 6 1 | . . 4 
-------+-------+-------
 . . . | . . . | . .[5]
 . . 4 | . . . | 3 . . 
 2 . 1 | . 5 . | 6 . 7 

Shall we write a petition to change it (they could reuse a 3 and a 9) ?

Isn't it a bit surprising that Sky One (or some sudoku fanatic) hasn't already changed it? (Or maybe they have -- I don't know its current condition.)