Sudoku Explainer

Keith Corlett's open-source Sudoku Explainer explains ANY Sudoku puzzle, and generates human puzzles. It's a Java (Swing) GUI based on DIUF Sudoku Explainer by Nicolas Juillerat (rewritten for speed) with all hinters from HoDoKu by Bernhard Hobiger, plus a few from sudopedia.com.

SE explains a simplest possible solution to ANY Sudoku puzzle. It's pretty fast. It generates basic (human solvable) Sudoku puzzles, but takes ages to generate difficult Sudokus. It cannot, except by chance, generate really hard puzzles (left to the boffins).

My coding ethos puts speed before maintainability, so multiple pieces of code implement the same pattern (boiler-plate), which is a pain in the ass to maintain.

Like all open-source software SE has bugs. It's a work in progress. This code is free, without any warranty (GNU LGPL).

It's intended to work for anyone, but my real focus is solving expert (beyond a humans ability) level puzzles as quickly as possible, using logic.