A Sudoku to try

Su Doku is a popular puzzle, perfect for passing time while travelling, for example. Your challenge is to complete the grid in such a way that each of the nine rows and columns, and each of the nine 3x3 squares contain all the between 1 and 9 exactly once.

Just like computer science, Su Doku builds on logic: you use rules to deduce the solution to the puzzle. As a programmer you need to be able to think clearly and methodically to work through a problem.

Try the one below - there is a more easily printable pdf version, in case you can't do it in your head :-)

Only look at the answer when you are done, or if really stuck.