Yet another Newbie :)

jdport · Posted: Wed Oct 19, 2005 8:21 pm Post subject: Yet another Newbie :)

I've only recently discovered Sudoku, and have found the puzzles to be very fun to solve. This happens to come at a time when I'm also looking to refresh programming skills and work with languages that I haven't done enough of to be good at (probably java) and so I decided I wanted to write a Sudoku generator/solver. I've read a lot of the posts on this board and there is a lot of good information, but I need some more information that is even more basic than most of what I've seen here...

First of all... I don't know what DLX, Swordfish, X-wing, hidden pairs, Coloring, etc, etc are. I realize they are standard algorithms because i've seen the terminology all over the internet as i've been reading various Sudoku sites but nobody who uses these terms ever define them. Maybe they are solving techniques I already know that I didn't have a name for, or maybe they can improve my solving skills, or maybe they are only programming tools... at any rate I'd really like to learn more about them, does anybody have a link that can maybe provide me more information about how these algorithm's work?

I'm trying to avoid looking at specific code ... I know that there are lots of solvers and generators out there and I could just grab one of those if I wanted to but the purpose of this is to work on my programming skills in a way that will be fun for me.

One further question about difficulty. I have read enough posts on this now to know that there will never be agreement on what it means for a puzzle to be difficult. Are there methods to generate puzzles though that will require specific methods to complete? I was introduced to Suduko through a book I bought at the store that rates the puzzles within as "gentle", "moderate", "tough", and "diabolical". The Gentle and Moderate puzzles are not too hard for me... they require basic logic and you can follow the progression from the beginning to the end. The Tough and Diabolical puzzles lead you to dead ends, where you need to choose between two possible numbers and follow it until it either takes you to a dead end (in which case you retrace your steps and try the other choice) or until it leads you to the solution. The Diabolical puzzles have more such "dead ends". Is there a way to know based on this idea of difficulty what kind of puzzle you are creating?

Thanks for the patience, there are obviously a lot of very smart and knowledgeable people following this forum, and I appreciate the pointers you post to the multiple newbie questions that I've seen Smile

-Jeff

SarC · Posted: Wed Oct 19, 2005 10:17 pm Post subject:

I'm a newbie myself, but here is some useful links that explain some of the different terms:

http://www.simes.clara.co.uk/programs/sudokutechniques.htm
http://angusj.com/sudoku/hints.php

And on a personal note, I can recommend trying out Simple Sudoku (http://angusj.com/sudoku/index.php). This program is great when you want to explore some of techniques - the program can give hints that illustrates when and where you can use the different techniques, which I found helps alot in the learning process Smile

. And its free for personal use! It's like christmas come early hehe

Cheers

jdport · Posted: Thu Oct 20, 2005 3:42 am Post subject:

Thanks for the links, those should help a lot with understanding the terminology. The more I learn about this puzzle the more I find out I don't know Smile

I had actually already downloaded the Simple Suduko program... a very nice program! I hope I can do as well if I ever successfully create my own. If I don't, at least I'll have that to play with Smile

-Jeff