Sudoku-Solver

This is my first project for learning python. A sudoku solver using the backtracking algorithm. Run main.py to play sudoku.

About Sudoku

Sudoku consists of filling a 9 x 9 cube of cells arranged in 9 subgroups of 3 x 3 cells, with numbers from 1 to 9, according to the restriction that the same number must not be repeated in the same row, column, or subgroup of 9.

A Sudoku has several cells with an initial value, so we must start solving the problem from this partial solution without modifying any of the initial cells.

Pseudocode Implementation for Sudoku Solver

This pseudocode outlines the logic for solving a Sudoku puzzle using backtracking.

Step 1: Initialize the Sudoku Board

Define the Sudoku board as a 2D array board with dimensions 9x9. Each cell contains numbers from 0 to 9, where 0 represents an empty square.

Step 2: Find Empty Squares

Create a function find_empty(bo) that iterates through the board to locate an empty square (represented by 0). Return the coordinates of the first empty square found; otherwise, return None.

Step 3: Validate Number Placement

Implement a function valid(bo, num, pos) to check if a number num can be placed at a given position pos. This involves checking the row, column, and 3x3 box for existing occurrences of the number.

Step 4: Solve Sudoku Using Backtracking

Create a recursive function solve(bo) that uses backtracking to fill in the board. It finds an empty square using find_empty, then tries placing numbers from 1 to 9 at the current position. If a number is valid and leads to a solution, it recursively attempts to fill the rest of the board. If no number can be placed, it resets the current position and continues with the next number.

Step 5: Print the Sudoku Board

Develop a function print_board(bo) to display the board. Include separators between rows and columns to clearly delineate the 3x3 boxes.

Step 6: Execute the Program

Finally, execute the program by printing the original board, attempting to solve it, and displaying the solved board if successful.

Resources used for this Projects

You can view the video tutorials i use to create this project here: https://www.youtube.com/watch?v=eqUwSA0xI-s&t=871s

You can learn more about Sudoku here: https://en.wikipedia.org/wiki/Sudoku

You can learn more about solving Sudoku here: https://en.wikipedia.org/wiki/Sudoku_solving_algorithms