A row is a sequence of digits that we represent symbolic integers

A Sudoku board is a sequence of 9 rows

Given a series of elements, make sure they are all different and they all are numbers between 1 and 9

Given a full Sudoku board, check that it is valid

A puzzle is simply a list of rows. Put 0 to indicate blanks.

Fill a given board, replacing 0's with appropriate elements to solve the puzzle

Solve a given puzzle and print the results

A random puzzle, found on the internet..

Another random puzzle, found on the internet..

Another random puzzle, found on the internet..

According to the web, this is the toughest. sudoku puzzle ever.. It even has a name: Al Escargot: http://zonkedyak.blogspot.com/2006/11/worlds-hardest-sudoku-puzzle-al.html

This one has been called diabolical, apparently

Another example

Solve them all, this takes a fraction of a second to run for each case