When you first crack open a new sudoku puzzle, do you look at the rows or columns first? Or do you work in blocks? What’s your strategy?
You must log in or register to comment.
For each number, I mark all cells where I know I can’t put it.
If one block, column or row has only one possible cell where a number can be, I put it there and then update all cells where I now know I can’t put it anymore.
This algorithm probably isn’t the fastest, but it’s easy to do manually and it has the advantage that you don’t need to backtrack.