Delay's Blog is the blog of David Anson, a Microsoft developer who works with the Silverlight, WPF, Windows Phone, and web platforms.
I'm not much of a Sudoku player, but I was recently in the company of some and got an idea for a Silverlight application to help solve Sudoku puzzles. There are already plenty of fine Sudoku programs out there, so I didn't set out to write "the world's best Sudoku program". Rather, this was an opportunity to explore some aspects of Silverlight that I haven't shown off yet such as audio, keyboard input, control embedding, and some more animation.
Sudoku is a surprisingly complex game and its puzzles range from very easy to quite difficult. Naturally, there are a number of different techniques that can be used to solve a Sudoku puzzle. Most of the techniques rely on keeping track of what the valid candidates for each cell are. Keeping track of all the candidates is too much for most people to do in their heads, so the common approach is to maintain a collection of pencilmarks. Keeping the pencilmarks up to date is a simple, monotonous task that involves no creativity whatsoever - and is perfect for a computer!
The Silverlight Sudoku Helper displays a Sudoku puzzle, automatically tracks the valid candidates, and leaves the creative problem solving fun to the user. It also prevents illegal moves and plays some fun sounds. :) The application looks like this:
You can click here (or on the image above) to play a game of Sudoku in your browser. As usual, I've made the complete source code available, so click here to download the source code and play around with it yourself! (To build the project, you'll want to use Visual Studio 2008 Beta 2 and the latest Silverlight Tools.)
I didn't know much about Sudoku when I started this project and it turned out to be a more involved game than I'd thought! I hope the Silverlight Sudoku Helper is fun and educational for others as well!