## Help me please

Advanced methods and approaches for solving Sudoku puzzles

### Help me please

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?
tekri

Posts: 3
Joined: 26 July 2005

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.
Karyobin

Posts: 396
Joined: 18 June 2005

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

Posts: 86
Joined: 26 March 2005

Heh heh - I win!
Karyobin

Posts: 396
Joined: 18 June 2005

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 ) ?
tekri

Posts: 3
Joined: 26 July 2005

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!)
Karyobin

Posts: 396
Joined: 18 June 2005

Done, thank's for advice.
tekri

Posts: 3
Joined: 26 July 2005

### help over solutions

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!
ivka

Posts: 6
Joined: 28 July 2005

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.
scrose

Posts: 322
Joined: 31 May 2005

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!
Last edited by ivka on Thu Jul 28, 2005 12:24 pm, edited 1 time in total.
ivka

Posts: 6
Joined: 28 July 2005

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

Posts: 6
Joined: 28 July 2005

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.
scrose

Posts: 322
Joined: 31 May 2005

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
ivka

Posts: 6
Joined: 28 July 2005

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

Posts: 322
Joined: 31 May 2005

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

Posts: 6
Joined: 28 July 2005

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