Q: How do we use constraint propagation to solve the naked twins problem?
A: In 'Naked Twins' problem main constraint is the fact that if two boxes are in the same unit and has the same two possible values, then any other boxes in this unit can't have this two values. Removing this two values for all common peers of this two boxes reduces search space.
Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: Diagonal constraint is very similar to any other basic constraints based on units: for each row, column, square or diagonal number from 1 to 9 should appear only once. For each of two diagonals, for each known value, this known value should be removed from the other boxes in this diagonal. That will reduce seach space.
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.
solution.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
Before submitting your solution to a reviewer, you are required to submit your project to Udacity's Project Assistant, which will provide some initial feedback.
The setup is simple. If you have not installed the client tool already, then you may do so with the command pip install udacity-pa.
To submit your code to the project assistant, run udacity submit from within the top-level directory of this project. You will be prompted for a username and password. If you login using google or facebook, visit [this link](https://project-assistant.udacity.com/auth_tokens/jwt_login for alternate login instructions.
This process will create a zipfile in your top-level directory named sudoku-.zip. This is the file that you should submit to the Udacity reviews system.