Sudoku Solver 9x9 Algorithm

This allows for an elegant description of the problem and an efficient solution.

Sudoku solver 9x9 algorithm. 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. Don t use backtracking for solving sudoku. Using algorithm x which is also a backtracking algorithm.

Start with an empty grid. A recursive function is a function that calls itself until a condition is met. Then click on the cells where you want to place the selected digit. This online sudoku solver uses donald knuth s dancing links algorithm to solve several sudoku implementations.

Sudoku puzzles may be described as an exact cover problem. The slightly more complicated dancing links algorithm has been discussed as well. 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. Programming a sudoku solver is not very difficult.

Modelling sudoku as an exact cover problem and using an algorithm such as knuth s algorithm x will typically solve a sudoku in a few milliseconds. Steps to generate a sudoku puzzle. I really don t understand how these replies can be serious. In this tutorial we ve discussed two solutions to a sudoku puzzle with core java.

Sudoku is a 9x9 matrix filled with numbers 1 to 9 in such a way that every row column and sub matrix 3x3 has each of the digits from 1 to 9. 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. After entering your puzzle press either. 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.

The code comes in two parts. Select a digit on the side of the grid first. The more interesting task is to write a human like sudoku solver that uses human possible techniques to identify the next move. Both solve the hardest puzzles within seconds.

Note that there are other approaches that could be used to solve a sudoku puzzle. 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. 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. 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.

Backtracking algorithms can be used for other types of problems such as solving a magic square puzzle or a sudoku grid. The current implementations are. The backtracking algorithm which is a brute force algorithm can solve the standard 9 9 puzzle easily. Generate a complete solution using backtracking that fills up the grid.