Sky One publicity gaffe

cyobiz · Posted: Mon Aug 15, 2005 6:09 pm Post subject: Sky One publicity gaffe

Hi, I'm new here. If my question has been answered before, I apologise.

See [url]http://www.sudoku.org.uk/blunder.htm[/url].

The article says that this puzzle has 1905 solutions. But I think there are 1906. Did anyone on this forum check this?

Cyobiz

Merri · Posted: Mon Aug 15, 2005 6:18 pm Post subject:

1905 is perfectly correct.

cyobiz · Posted: Mon Aug 15, 2005 7:18 pm Post subject:

Hmm.. My solver says 1906, but of course it may be full of bugs, I don't know. How many solutions does this one have you think:

..1..47..
...7...38
6..9.845.
4.9......
.7.....1.
......3.9
.521.7..4
78...9...
..68..5..

Cyobiz

Merri · Posted: Mon Aug 15, 2005 7:22 pm Post subject:

Three it tells me there to be. If you want, you can see my topic below and get my program from there and do comparisons.

cyobiz · Posted: Mon Aug 15, 2005 8:10 pm Post subject:

I found 9 solutions..

It is awfully difficult to check that they are all different, but I think they are.

831654792 | 821534796 | 831254796
945712638 | 945716238 | 945716238
627938451 | 637928451 | 627938451
419385276 | 419385627 | 419385672
273496815 | 573492815 | 573492815
568271349 | 268671349 | 268671349
352167984 | 352167984 | 352167984
784529163 | 784259163 | 784529163
196843527 | 196843572 | 196843527

831654792 | 821534796 | 831524796
945712638 | 945716238 | 945716238
627938451 | 637928451 | 627938451
419386275 | 419385672 | 419385627
273495816 | 573492815 | 573492815
568271349 | 268671349 | 268671349
352167984 | 352167984 | 352167984
784529163 | 784259163 | 784259163
196843527 | 196843527 | 196843572

831654792 | 831254796 | 831524796
945712638 | 945716238 | 945716238
627938451 | 627938451 | 627938451
469381275 | 419385627 | 419385672
273495816 | 573492815 | 573492815
518276349 | 268671349 | 268671349
352167984 | 352167984 | 352167984
784529163 | 784529163 | 784259163
196843527 | 196843572 | 196843527

Now how to be sure about the "Sky publicity stunt" number of solutions...

Cyobiz

Merri · Posted: Mon Aug 15, 2005 8:21 pm Post subject:

There are atleast two exact same solutions: the third and the ninth. Six and eight seem to match too.

Urgh, thinking typo

cyobiz · Posted: Mon Aug 15, 2005 8:34 pm Post subject:

How do you count them?

1 2 3
4 5 6
7 8 9 ?

In that case the third and the ninth are different. The eighth row in 3 and 9 is respectively

7 8 4 5 2 9 1 6 3
7 8 4 2 5 9 1 6 3

interchanging 2 and 5.

Cyobiz

Merri · Posted: Mon Aug 15, 2005 8:57 pm Post subject:

Number blindness caught me and should be sleeping already. The results seem to be valid. Counter is a late addition to my program at the moment, however it has given correct results this far. At the moment I have no idea where it could be missing a testable number, thus missing a possible solution.

Simes · Posted: Mon Aug 15, 2005 8:58 pm Post subject:

My solver says 1905... and it'll show you the lot too if you want to see them.

Follow the link below.

Simes
_________________
Simes
www.sadmansoftware.com/sudoku

Merri · Posted: Mon Aug 15, 2005 9:09 pm Post subject:

cyobiz: you have invalid sudokus there. Second, third, fifth, sixth, eight and ninth have numbers 5 in the each end of the middle row.

573492815

cyobiz · Posted: Tue Aug 16, 2005 9:11 am Post subject:

(...)
Right, so my solver reallyis full of bugs. Thanks... back to the drawing board..

Amazing; in my calculation of the sky sudoku there was ONE invalid result, raising the total to 1906. That one also had a double 5 in a row..

cyobiz · Posted: Tue Aug 16, 2005 10:50 am Post subject:

I found the bug. One step which was little bit too greedy. Thanks, Merri. I should have thought of testing the solutions for 'validity' first; I only checked them for 'being different'.