PHP implementation of solution described by Peter Norvig
Norvig's extremely lucid exposition and Python implementation are published here:
http://norvig.com/sudoku.html
Comments, tests, and notes have been added to this PHP implementation with the goal of making it as easy to understand as the original.
To run (as any user), type 'php sudoku.php'.
Copyright (c) 2017 Peter Wolfenden See the LICENSE file for details.