I need your help

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I need your help

Postby Joulies » Tue Mar 28, 2006 4:29 pm

Hello. I am having serious problem with a sudoku table. I have been trying to solve it for like two days and I mean that. I even downloaded a solver, something that I've never done to any other table before. But this one really looks bizzare to me.
Yes I have the solution but I want to see a hint to that point I am stuck. I present you the table to its original shape and up to the point I managed to solve it.

|7 _ _|_ 9 _|_ _ 2| * * * * * |7 _ _|4 9 _|_ 1 2|
|_ _ _|6 _ 1|_ _ _| * * * * * |_ _ _|6 7 1|_ _ _|
|_ _ 1|3 _ _|6 7 _| * * * * * |_ _ 1|3 _ _|6 7 _|

|_ _ _|_ 6 _|_ 9 _| * * * * * |_ 7 _|_ 6 _|_ 9 _|
|6 _ _|7 _ 4|_ _ 3| * * * * * |6 _ _|7 _ 4|_ 2 3|
|_ 8 _|_ 1 _|_ _ _| * * * * * |_ 8 _|9 1 _|_ 6 7|

|_ 4 7|_ _ 9|2 _ _| * * * * * |_ 4 7|1 _ 9|2 _ 6|
|_ _ _|5 _ 7|_ _ _| * * * * * |_ _ _|5 _ 7|_ _ _|
|3 _ _|_ 4 _|_ _ 1| * * * * * |3 _ _|_ 4 6|7 _ 1|

I know that the second table is correct. But I really want you to give me a hint on how to continue.
Thanx
A sudoku crazy fella from Greece
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Postby tarek » Tue Mar 28, 2006 4:55 pm

If this is your regular sudoku, then I'm afraid it has multiple solutions....

The reason why is that you can interchange freely Columns 4,5,6 & still have a valid solution....

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Postby ravel » Tue Mar 28, 2006 4:59 pm

You can solve it with an xwing for number 9 in rows 5,9/cols 2,3, which allows you to eliminate 9 from r3c2.

Tarek, in every unique puzzle you can interchange the columns of a stack to get a unique solution - it is a different, but equivalent puzzle then.
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Postby tarek » Tue Mar 28, 2006 6:31 pm

I must be missing something here ravel, what is a sudoku table?

Is it some kind of variant?

what I can see are 3 puzzles, all have columns 4,5,6 empty...... if this is a regular "vanilla" sudoku, you can't reach a solution using x-wing. The only way is through guessing or using the 1-solution based logic.

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Postby TKiel » Tue Mar 28, 2006 8:14 pm

I think the sort of candidate grid thing on the left are the initial clues:
Code: Select all
|7 _ _|_ 9 _|_ _ 2|
|_ _ _|6 _ 1|_ _ _|
|_ _ 1|3 _ _|6 7 _|

|_ _ _|_ 6 _|_ 9 _|
|6 _ _|7 _ 4|_ _ 3 
|_ 8 _|_ 1 _|_ _ _| 

|_ 4 7|_ _ 9|2 _ _|   
|_ _ _|5 _ 7|_ _ _| 
|3 _ _|_ 4 _|_ _ 1|   

And the thing on the right is the point to which it has been solved:
Code: Select all
|7 _ _|4 9 _|_ 1 2|   
|_ _ _|6 _ 1|_ _ _|
|_ _ 1|3 _ _|6 7 _| 

|_ 7 _|_ 6 _|_ 9 _|
|6 _ _|7 _ 4|_ 2 3|
|_ 8 _|9 1 _|_ 6 7|

|_ 4 7|1 _ 9|2 _ 6|
|_ _ _|5 _ 7|_ _ _|
|3 _ _|_ 4 6|7 _ 1|


I entered it into SS and it only has one solution.

Tracy

(Edited to make second grid same as original post. My apologies.)
Last edited by TKiel on Tue Mar 28, 2006 8:17 pm, edited 1 time in total.
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Postby tarek » Tue Mar 28, 2006 10:00 pm

Ah... I see it now, This is a first one....

Thanx for confusing me Joulies, I hope that next time the puzzle is posted using the standard format.......

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Postby Tumbleweed » Tue Mar 28, 2006 10:48 pm

ravel wrote:You can solve it with an xwing for number 9 in rows 5,9/cols 2,3, which allows you to eliminate 9 from r3c2.

Tarek, in every unique puzzle you can interchange the columns of a stack to get a unique solution - it is a different, but equivalent puzzle then.


Isnt a simpler option to observe that the only place 4 can go in column 4 is in row 1? Unless I have copied it down wrongly? (this is in the 'solved as far as I can go' second table)

Tw
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Postby TKiel » Wed Mar 29, 2006 12:31 am

Tumbleweed,

If you used my post as the source, the grid was not the same as in the original post, for which I apologize. I must have deleted a couple of numbers by mistake. My post above has been edited to reflect the grid as it is shown in the first post in this thread.

Tracy
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Postby tso » Wed Mar 29, 2006 3:06 am

Code: Select all
 7 . . | 4 9 . | . 1 2
 . . . | 6 7 1 | . . .
 . . 1 | 3 . . | 6 7 .
-------+-------+------
 . 7 . | . 6 . | . 9 .
 6 . . | 7 . 4 | . 2 3
 . 8 . | 9 1 . | . 6 7
-------+-------+------
 . 4 7 | 1 . 9 | 2 . 6
 . . . | 5 . 7 | . . .
 3 . . | . 4 6 | 7 . 1



The 9 in box 9 MUST be in row 8.
Therefore, the 9 in column one MUST be in box 1.
Therefore, r3c2<>9.

The 2 in box 2 MUST be in row 3.
Therefore, r3c2<>2.

That leaves 5 as the only digit left that can go in r3c2.

It should be easy after that.
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