SudokuSolver

Introduction

This is a java implementation of a Sudoku solver which was initially posted to me as a java exercise question from my IS200 IS Foundations course. I'm posting this up for the fun of it.

Currently a brute-force, backtracking (BFBT) algorithm is used to solve the puzzle and is inefficient at puzzles with minimal hints. One of the highest-difficulty puzzle currently takes approximately 1000 milliseconds under this algorithm.

Usage

This solver takes in 81 arguments, one for each cell, separated by a space, as the initial puzzle state.

$ java SudokuSolver \
	0 6 3 4 9 0 0 0 1 \
	0 0 0 0 0 0 7 0 9 \
	0 1 9 0 0 0 0 0 0 \
	0 0 1 0 0 2 9 3 0 \
	9 0 0 1 0 7 0 0 2 \
	0 7 8 9 0 0 4 0 0 \
	0 0 0 0 0 0 8 2 0 \
	3 0 6 0 0 0 0 0 0 \
	4 0 0 0 2 9 1 7 0

TODO

There are plans to implement the following:

1. Improve the current brute-force, backtracking (BFBT) algorithm by iterating through a list of valid numbers in random order, rather than just blindly going through 1–9.
2. Supersede the current BFBT algorithm with Dancing Links (DLX), keeping BFBT as an option.

Contributions

All suggestions on improving efficiency, or coding improvements, are welcome via pull requests.