Q: How do we use constraint propagation to solve the naked twins problem?
A: The technique to solve naked twins can reduce the complexity of the puzzle.
We can treat naked twins as a strategy just like eliminate or only choice.
I think the best place to use naked twins is the reduce_puzzle() function.
So that we can repeatedly enforce the constraints on the board to reduce the search space.
Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: One the two main diagonals, the numbers 1 to 9 should all apear exactly once.
The same rule applied on the units as well.
We can handle two main diagonals as additional units.
By add two diagonals into definition of units,
we can introduce the diagonal constraints to our solution without any other changes.
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_value 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 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.