Q: How do we use constraint propagation to solve the naked twins problem?
A: Naked twins occur when there are two boxes in the same unit with identically the same values for the allowed digits, and with the number of allowed digits being two. In this case, we simply eliminate these two possibilities from the other rows in the unit.
Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: We deduce constraints that follow from the logic of the sudoku puzzle. For a diagonal sudoku problem, these includes the constraint on the diagonals. In particular we elimiminate unallowed digits, apply the naked twins operation, and fill in boxes when there is only one allowed valued for that box. These prunes the space of possibilities. We do this recursively and apply depth first search in a smart way, only branching out along a path with the smallest number of possibilities each time, until we find the solution.
This project requires Python 3.
We recommend students install Anaconda, a pre-packaged Python distribution that contains all of the necessary libraries and software for this project. Please try using the environment we provided in the Anaconda lesson of the Nanodegree.
Optionally, you can also install pygame if you want to see your visualization. If you've followed our instructions for setting up our conda environment, you should be all set.
If not, please see how to download pygame here.
solutions.py- You'll fill this in as part of your solution.solution_test.py- Do not modify this. You can test your solution by runningpython solution_test.py.PySudoku.py- Do not modify this. This is code for visualizing your solution.visualize.py- Do not modify this. This is code for visualizing your solution.
To visualize your solution, please only assign values to the values_dict using the assign_values function provided in solution.py
The data consists of a text file of diagonal sudokus for you to solve.