# Looking for a Sudoku Algorithm to implement in Ruby

**URL:** <https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800>\
**Category:** Ruby\
**Created:** [November 10, 2007, 5:51pm UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800 "2007-11-10T17:51:37Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [November 10, 2007, 5:51pm UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800/1 "2007-11-10T17:51:37Z")

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Hey,

Did anyone know of a Sudoku algorithm, which I can use to implement a  
Ruby  
solution?  
Although I can solve Sudoku without much difficulty, I can’t say the  
same  
when I try to write a Ruby program to solve Soduku.

Thanks,

Victor

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**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [November 10, 2007, 6:37pm UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800/2 "2007-11-10T18:37:47Z")

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Victor R. wrote:

> Did anyone know of a Sudoku algorithm, which I can use to implement a Ruby  
> solution?

You might want to have a look at Ruby Q. #43 (Sudoku Solver):  
[http://www.rubyquiz.com/quiz43.html](http://www.rubyquiz.com/quiz43.html)

Alternatively you could also solve it using constraint programming with  
Gecode/R: [http://gecoder.rubyforge.org/examples/sudoku.html](http://gecoder.rubyforge.org/examples/sudoku.html)

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<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [November 10, 2007, 7:19pm UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800/3 "2007-11-10T19:19:00Z")

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Hi…

The following projects on codeproject may give you some ideas…

[http://www.codeproject.com/csharp/sudoku.asp](http://www.codeproject.com/csharp/sudoku.asp)  
[http://www.codeproject.com/useritems/sudoku\_solver.asp](http://www.codeproject.com/useritems/sudoku_solver.asp)  
[http://www.codeproject.com/useritems/sudoku.asp](http://www.codeproject.com/useritems/sudoku.asp)  
[http://www.codeproject.com/miscctrl/XSudokuWnd.asp](http://www.codeproject.com/miscctrl/XSudokuWnd.asp)

Thanks,  
Hari

PS : This is my first post. Sorry if I should not post links to other  
language articles. just wanted to help…

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<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [November 10, 2007, 10:46pm UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800/4 "2007-11-10T22:46:21Z")

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Thanks to everyone for your suggestions and recommendations.  
I truly appreciate all your input.

Thanks again,

Victor

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<div class="post-metadata">

**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [May 12, 2008, 11:27am UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800/5 "2008-05-12T11:27:42Z")

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> Looking for a Sudoku Algorithm to implement in Ruby  
> Posted by Victor R. (Guest) on 10.11.2007 17:51  
> Hey,
> 
> Did anyone know of a Sudoku algorithm, which I can use to implement a Ruby solution?  
> . . .

Here’s yet another one:

Sudoku solver in Ruby using SAT (Boolean satisfiability problem)

[http://eli.thegreenplace.net/programs-and-code/](http://eli.thegreenplace.net/programs-and-code/)

Cheers,

j.k.

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**Author:** ![ribes](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/f4b2a3/32.png) [@ribes](https://www.ruby-forum.com/u/ribes)\
**Post date:** [November 10, 2007, 10:15pm UTC](https://www.ruby-forum.com/t/looking-for-a-sudoku-algorithm-to-implement-in-ruby/119800/6 "2007-11-10T22:15:30Z")

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On Nov 10, 10:50 am, Victor R. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hey,
> 
> Did anyone know of a Sudoku algorithm, which I can use to implement a Ruby  
> solution?

The Soduku puzzle can be solved in a few seconds by a very simple  
backtracking algorithm:

current\_cell = first\_empty\_cell

while true  
if put\_next\_possible\_number\_in\_current\_cell  
if all\_cells\_filled  
print\_solution  
exit  
else  
current\_cell = next\_empty\_cell  
end  
else if current\_cell = first\_empty\_cell  
raise Exception.new(“no solution”)  
else  
current\_cell = previous\_empty\_cell  
end