Sudoku Solver 9x9 Algorithm

To solve a sudoku puzzle download the two files enter the sudoku matrix that you want the algorithm to solve at the top of solve sudoku m an example for the.

Sudoku solver 9x9 algorithm. In this post i will introduce a sudoku solving algorithm using backtracking if you don t know about backtracking then just brush through the previous post. Select a digit on the side of the grid first. Sudoku puzzles may be described as an exact cover problem. Steps to generate a sudoku puzzle.

The more interesting task is to write a human like sudoku solver that uses human possible techniques to identify the next move. This free online sudoku solver can solve any valid sudoku puzzles with a smart option to show the rationale of each step a good way to learn the solving techniques by examples. Backtracking algorithms rely on the use of a recursive function. An alternative approach is the use of gauss elimination in combination with column and row striking.

Then click on the cells where you want to place the selected digit. In this tutorial we ve discussed two solutions to a sudoku puzzle with core java. Start with an empty grid. The regular sudoku the sudoku x also known as diagonal sudoku the irregular sudoku also known as jigsaw sudoku or nonomino sudoku the irregular sudoku x the hyper sudoku also known as nrc sudoku the hyper sudoku x the extra region sudoku the odd.

This online sudoku solver uses donald knuth s dancing links algorithm to solve several sudoku implementations. Both solve the hardest puzzles within seconds. The backtracking algorithm which is a brute force algorithm can solve the standard 9 9 puzzle easily. It s a bounded 9x9 sudoku backtracking isn t going to fail because of variable stack size.

After entering your puzzle press either. The current implementations are. Using algorithm x which is also a backtracking algorithm. We re going to use the backtracking algorithm to generate sudoku puzzles and pretty much the same algorithm will be used to solve the puzzles as well.

Note that there are other approaches that could be used to solve a sudoku puzzle. I really don t understand how these replies can be serious. Backtracking algorithms can be used for other types of problems such as solving a magic square puzzle or a sudoku grid. Even though sudokus are known to be np complete because the n in a 9x9 sudoku is fairly small brute forcing a solution can be done in a few seconds.

The code comes in two parts. This allows for an elegant description of the problem and an efficient solution. Generate a complete solution using backtracking that fills up the grid. A recursive function is a function that calls itself until a condition is met.

Anydouble m which checks whether there are any numbers that appear twice in any row column or 3x3 box and solve sudoku m which is the main file. The slightly more complicated dancing links algorithm has been discussed as well. Programming a sudoku solver is not very difficult. It s like these commenters haven t ever coded before.