How do Sudoku setters set Sudokus?

Question

It must be computer generated. But some are cleverer than others (and make more money at it - eg the guy in The Daily Telegraph). Is it simply the reverse of solving a sudoku, encoded? (Fiendish is no problem with logic.) Or is it more sophisticated than that?

Answer 1

I just finished a computer programming class in which we had to make a 9 x 9 Sudoku puzzle. It basically boils down to randomly filling in a row and then checking three conditions:

row, col, and subgrid violations. If the row doesn't violate any of these requirements, then it's a good row and you move down to generate the next row. If the row is bad, then you regenerate another random row.

It was actually a lot of fun for me. I was learning C++

Answer 2

You can just put in random numbers in random places (obviously making sure it doesn't break the rules of sudoku) You can make them harder by giving less numbers or spread out more and stuff