The New Sudoku Players' Forum

[tekri]

On newspaper was following sudoku:
_ _ 6 4 1 3 7 _ _
_ 1 _ 6 7 9 _ 4 _
_ _ _ _ _ _ _ _ _
6 _ _ _ _ _ _ _ 9
_ 7 4 _ _ _ 2 5 _
2 _ _ _ _ _ _ _ 7
_ _ _ _ _ _ _ _ _
_ 9 _ 3 5 2 _ 6 _
_ _ 3 1 6 7 5 _ _

I'm end at:
_ _ 6 4 1 3 7 _ _
_ 1 _ 6 7 9 _ 4 _
_ _ _ 2 8 5 _ _ _
6 _ _ 7 2 _ _ _ 9
_ 7 4 _ _ _ 2 5 _
2 _ _ 5 _ _ _ _ 7
_ 6 _ _ _ _ _ 7 _
_ 9 _ 3 5 2 _ 6 _
_ _ 3 1 6 7 5 _ _


I don't know, how to next,
can anyone help with least one number?

[Karyobin]

If you examine row 9 (and make a few pencil marks, probably), you'll see there's only one place for a number 9 to go.

Good luck with the rest of it.

[SteveF]

Have a good look at row 9. You should be able to find a candidate that can only go in one cell.

[Karyobin]

Heh heh - I win!

[tekri]

Ok, now I'm on:
9 _ 6 4 1 3 7 _ _
_ 1 _ 6 7 9 _ 4 _
_ _ _ 2 8 5 9 _ _
6 _ _ 7 2 _ _ _ 9
_ 7 4 _ _ _ 2 5 _
2 _ 9 5 _ _ _ _ 7
_ 6 _ _ _ _ _ 7 _
_ 9 _ 3 5 2 _ 6 _
_ _ 3 1 6 7 5 9 _

can you help me please again (I'm probably blind ) ?

[Karyobin]

Well, we certainly could, but on having another look at the pencil marks there are a lot of ways into this puzzle. I'd like to recommend you read some of the entries of:

http://www.angusj.com/sudoku/hints.php

and

http://www.simes.clara.co.uk/programs/sudoku.htm

They're very good and they'll teach you all sorts of logical procedures for getting past the problems you're currently experiencing.

One to be going on with though...

Look where to place a '2' in column 8. (You don't even need pencil marks for that one!)

[tekri]

Done, thank's for advice.

[ivka]

Hi! i just started solving sudoku, and just managed
to solve my first sudoku! at first it seemed correct, but my solution differs from that in newspapers! is it possible that one puzzle has several possible solutions? thank you very much!

[scrose]

It is possible for a puzzle to have multiple solutions, although this is generally undesirable and is usually considered a poorly-formed puzzle. There are a couple possibilities: the newspaper published a puzzle that has multiple solutions, or the puzzle has a unique solution but you made a mistake when solving it. If you post the starting grid and the name of the newspaper it appeared in, someone will likely be able to tell you if the puzzle has multiple solutions.

[ivka]

The newspapers are Jutarnji list (Croatia), published on July 24th 2005, and here is the whole puzzle:

- 7 - - 9 6 - - -
- - - 2 - - - - 8
- - 2 7 - - 4 - -

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

- - 5 - - 9 8 - -
2 - - - - 3 - - -
- - - 5 2 - - 3 -

thank you!

[ivka]

I apologize for the look of the puzzle, when I was rewrighting it in a message box it looked better!

[scrose]

That puzzle has only one solution. You must have made a mistake when solving it. If you post your solution, I might be able to spot what you did wrong.

You can use the [code][/code] tags to get a fixed-width font.

[ivka]

here is my solution:

Code: Select all

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

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

[scrose]

The first thing I spotted was that you have two 9's in box 2. This breaks the rule of sudoku.

[ivka]

yes, I've just spoted that! and i was so proud of myself!
well, back to work!
thank you for your help!