Solve Sudoku Puzzles using Excel [because it is weekend]

Posted on October 23rd, 2009 in VBA Macros - 13 comments

Sanjay, my colleague is an avid programmer and excel enthusiast. In his spare time he wrote a small VBA macro to solve Sudoku. Sudoku is a very famous number based puzzle with a 9×9 grid of cells. Each of the 9 rows, columns and 3×3 blocks should be filled in such a way that they have all the numbers from 1 to 9. Sudoku is a very effective way to keep your brain cells ticking. I am a huge sudoku fan and I solve sudoku whenever I have few minutes to kill. So naturally I jumped with joy when I saw Sanjay’s excel macro for solving sudoku. He is kind enough to let me share this with all of you.

Solve Sudoku using Excel

Click here to download the sudoku solver workbook. It has macros, so enable them when you download the file.

The file is unlocked, so if you are curious, go around and poke the code.

And if you are interested in writing your own sudoku solver, here is a basic algorithm:

  • While Sudoku is not solved,
    • Check if any row, column or 3×3 block has ‘n’ cells such that, (n>1)
      • All possible values in those ‘n’ cells are exactly ‘n’ unique values
    • For each block of such cells,
      • Remove the occurrences of the ‘n’ unique values from remaining cell’s possible’s list in that row / column / 3×3 grid
    • Check if any cell has more than one possible value. If so, Sudoku is not solved.
  • Do While

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13 Responses to “Solve Sudoku Puzzles using Excel [because it is weekend]”

  1. Arnold says:

    Hi PHD

    Is there an excel sudoku creator, my mother in law can’t stop doing them and buying books is expensive?
    Regards

  2. cdascgil says:

    Only works for simple puzzles.
    Nice macro, though

  3. Arnold says:

    Hi maybe my question was not understood.
    Is there a free excel program to create suduko puzzles or free suduko pc game
    thanks

  4. Yogesh Gupta says:

    Dear Arnol – here is the link for what you want.
    http://www.harismind.com/sudoku.html

  5. Stružák says:

    @PHD: Another masterpiece. 8-)

    @Arnold: You can try the Sudoku Generator at http://www.opensky.ca/~jdhildeb/software/sudokugen/. This one does not use Excel, but can be usefull as well.

  6. Modeste says:

    Dear Arnold,
    Assuming knowing the rules to form a given Sudoku and fully completed,
    there are a multitude of grids with the same relations
    that is to say:
    – Permutations digit numbers
    – Rotations per group of columns or rows
    – But also rotations in groups

    applying these principles to a bank of model grid
    it is possible to generate and print indefinitely differents grids for pleasure always renewed …

    That’s what I have done :
    http://www.cijoint.fr/cjlink.php?file=cj200910/cij9dWRCr1.xls

    – I don’t create any of the original model grids, nor the soluce proc
    – the worksheet is protected with blank

    Print and Enjoy !!!

  7. David says:

    It seems that others have successfully opened this file, so what am I doing wrong? I can’t see a workbook in the zip file so can’t even look at it! (It probably doesn’t matter, because I only have Excel 2003.)

    The content of the file I downloaded didn’t seem to have anything to do with Sudoko. (It has folders _rels; docProps; & xl).

  8. Chandoo says:

    @cdascgil: Thank you. I have noticed it too. But the macro stops after 10 iterations. May be you can increase the number and see if it solves the tougher ones.

    @Struzak: Thank you. and thanks for the link to sudoku generator.

    @Modeste: Wow, that is cool.

    @David: try now, I have uploaded the Excel 2007 version originally. Now I have replaced the file with an Excel 2003 compatible version.

  9. Sanjay Kalrani says:

    Thanks Chandoo..I missed this post of yours.
    1) Just as I did this, I was pretty much interested in creating an excel that could generate SUDOKU puzzles.
    2) I haven’t tried more than 10 iterations..but yes, more difficult problems would get solved if you increase the iterations in the code.

    Sanjay

  10. […] Solve Sudoku Puzzles using Excel Macros – Excel Games …How to Create a Suduko Puzzle. Sudoku is a Japanese number placement game that has fast become a mainstay in daily newspapers across the world. […]

  11. Gana says:

    Super nice :)

  12. Venu Gopal says:

    I wrote an Excel/VBA Sudoku Puzzle Teacher /Puzzle Solver program in Excel/VBA with about 3000 lines of VBA code :  Sudoku Teacher Sudoku Helper.  You can use it to learn Sudoku or use it to learn Excel / VBA programming.

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