Sudoku Solver
I wrote this as a personal project to scratch an itch of my own. I know that there are other solutions to this problem, but I wanted to write my own.
I had been thinking of solving Sudoku puzzles using a tree of permutations for a while before I actually wrote any code. I wanted a permutation algorithm that:
- Could start in any state
- Kept the minimum amount of data
- Could be tailored to ignore Sudoku fixed cells
I tried a couple of different permutation algorithms, but they fell short in one way or another.
What I found and used instead was the Johnson Trotter Algorithm. It met all of my criteria, is fast, and has very little overhead.
http://www.cut-the-knot.org/Curriculum/Combinatorics/JohnsonTrotter.shtml http://www.nist.gov/dads/HTML/johnsonTrotter.html
