878.518 downloads thanks to you!

Henk · Posted: Fri Jun 20, 2008 10:21 pm Post subject: 878.518 downloads thanks to you!

Hi,

My first post on this forum was on nov 13, 2005. The sudoku hype in Holland just began and I was fascinated by it. This Sudoku puzzle that is based on simple mathematics. I wrote a small simple sudoku solver. I didn't enjoy solving these puzzles by hand, but I liked coding the logic in a progam a lot.

I found it pretty hard to let the program 'think' like a human and solve the puzzle in the same way as a real person should do it very difficult. This became like an obsesion for a short while. A few weeks I worked very hard on a simple program that was able to help solve puzzles. Pretty soon I had something I thought was good enough to public on the web. I openend www.intosudoku.com and the first month I recieved over 140.000 visitors. The site went down..... datalimit reached.... a few days later the site went up again. The months after 290.000 visitors. Sudoku was really popular, and I was not prepared for this amount of publicity. The program was free to download and free to use. But the hosting needed money so I opened a paypal account and started accepting donations. The next versions I started to 'limit' the extra expert-functions like searching for backdoors, finding very specific puzzles and generate a number of puzzles to export them to pdf. At the time there where just a few popular programs around, simple sudoku was one of them.

I was very suprised that there where people that bought a license! Its just a very simple program that I made in my spare time, and there where people interrested in it. It even got better! I was contacted to deliver 120 puzzles for a puzzlebook, got contacted for a puzzle book to use some of texts and images and even got contacted by a few schools to use the program for education. Too bad I'm just a programmer, and not a salesman. I probably should have earned millions.. Laughing

well I didn't, I just earned enought for the hosting and thats about it. But thats ok, I think that its great to just write something for fun in 2005 and still get about 6.000 downloads a month 3 years later.

Well I just wanted to say hello again, I haven't been around here for a while. Programming a sudoku solver has been great fun! I'm done with it, there probably are great solvers around now that are better then the one I wrote.

Kindest Regards,
Henk Westhuis
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Generate and solve Sudoku puzzles with Into Sudoku!

wapati

Henk · Posted: Sat Jun 21, 2008 6:04 am Post subject:

You are right about me quit a while ago adding new techniques. The latest I did was perfecting the forcing chains solving part november 2007. I also do not think more techniques make the program more advanced. Its the solving path. Most programs just use a lot of techniques, while there is a easier solving path. I did try solving this problem by showing the 'backdoors' of a puzzle. A backdoor is a singe step that breaks the puzzle. About every puzzle has multiple backdoors, solving a backdoor in the least possible steps is pretty hard.

There were a lot of requests on the forum, before it got overrun by spam, but I just cannot find the motivation to implement more techniques. I had some plans for making a multiplayer version using IRC as a protocol, but I failed getting it stable.

Right now I'm writing another small sudoku application, just to learn the new Silverlight2.0 framework Microsoft released.

Are there any programmes around where most known techniques are implemented? I know SudoCue has a few.
_________________
Generate and solve Sudoku puzzles with Into Sudoku!

wapati · Posted: Sat Jun 21, 2008 6:40 am Post subject: