A Sudoku solver is a computer program or algorithm designed to automatically solve Sudoku puzzles. The solver takes a partially filled Sudoku grid as input and applies logical rules and strategies to determine the correct placement of numbers in the empty cells. The goal is to fill in the entire grid according to the rules of Sudoku.
Here are the general steps that a Sudoku solver algorithm might follow:
- Input: Receive a partially filled Sudoku grid as input, where some cells already contain numbers, and others are empty.
- Logic and Rules: Apply a set of logical rules and strategies to determine the possible candidates for each empty cell. Common strategies include checking rows, columns, and subgrids for missing numbers and eliminating possibilities based on the existing numbers in those regions.
- Candidate Elimination: Use the identified candidates to eliminate possibilities for other cells in the same row, column, and subgrid. This process helps narrow down the options and make more precise placements.
- Backtracking: If the solver reaches a point where no logical moves can be made, it may employ backtracking. Backtracking involves undoing the most recent placements and trying alternative candidates until a valid solution is found.
- Completion: Continue the process of deduction, elimination, and backtracking until the entire Sudoku grid is filled, meeting all the rules of the game.
Sudoku solvers can vary in complexity and efficiency. Some solvers use advanced techniques and algorithms to quickly solve even the most challenging Sudoku puzzles, while others may rely on simpler strategies suitable for easier puzzles. The goal of a Sudoku solver is to demonstrate that a given puzzle has a unique solution and to find that solution.