Basic Sudoku Solver

This is a python code for a Sudoku solver using a GUI created with the tkinter library. It has two main parts: the solve_sudoku function and the SudokuSolver class.

The solve_sudoku function is a Recursive Implementation of the Backtracking Algorithm to solve a 9x9 sudoku puzzle. It iterates over the grid and when it finds a cell with a value of 0, it tries to fill it with a number from 1 to 9. If the number is valid, it moves on to the next cell, otherwise it backtracks.

The SudokuSolver class is responsible for creating the GUI. It initializes a 9x9 grid, creates a dictionary of tkinter. Entry widgets for each cell, and creates a button to solve the sudoku. When the "Solve" button is clicked, the function retrieves the values from the cells and passes them to the solve_sudoku function. If a solution is found, it updates the values in the GUI, otherwise it shows an error message.

Also, there is an is_valid function to check if a number is valid in the current cell.

Finally, the root Tk object is created and the SudokuSolver is instantiated and associated with it, and the mainloop method is called to start the GUI event loop.