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.

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 occ