@Olegkovtun - Wow, that one is great. Very clever, efficient, readable, and understandable. I am super impressed with yours.

The chosen answer above is clever in that it uses very few lines but it fails in the other 3 categories so I am not sure why some people voted it as a best practice.

My solution has only 2 cycles, less code and clear enough :)

Its arguinging whos solution is more understandable) Lets do some refactoring and compare our solutions for clearing.

faster but, longer and not clear

I think my solution is faster

Do you think that you have better solution?

and...?

But, we don't have resizable array, we know that sudoku has constant amount of cell - 9*9)

Dont see 4 loops everyday))) And your solution not very efficient, if I understand your solutin correct, its O(n2), isnt it?

Can you explain why?

Some crazy solution