dailysudoku.com

[telflonmail]

Hi,

I have done the 19-Jan-2006, [the very hard ] and have found it has 2 correct solutions. This was my last move - where the 5 and 7 could be interchanged and everything would be correct.

5 x x x x 7 x x x
x x x x x x x x x
7 x x x x 5 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 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 5 and the 7 could be interchanged cleanly to meet suduko. So, which on is the more correct version (or are both) :-)

So, the top left, top middle could be:

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

or:

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

I hope I didn't give away too much - this one was pretty straight forward, as long you worked the definite singles first before keeping score of the doubles and triples and eliminate as you go along.

[David Bryant]

[geoff h]

Hi there,

Well, I think I have to concur with David on this one - unfortunately it appears that both of telflonmail's solutions are incorrect and that David's solution is the one true solution.

Here's what I had after 34 moves :

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

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

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

Therefore, when considering Row 1, you can see a pair of 5,7 in r1c1 and r1c6. This means you MUST place Nr 1 in r1c5 and then Nr 6 in r1c4. The puzzle is easily solved from there and the first two boxes then read as follows;

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

Which is what David came up with.

Cheers,
Geoff

[telflonmail]

my bad!

I transcribed two of the givens to the wrong cell when making a larger grid. So kindly ignore above ramble.

Cannot beat a computer generated sudoku

[jia]

just one solution