Q: How do we use constraint propagation to solve the naked twins problem?
A: If two boxes in a unit share the same pair of possible values, we know that no other box in that unit can have either of those values.
This means we can remove those values from every other box in the unit. This constrains the problem by reducing the number of possibilities for a boxes that share a unit with the twins.
Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: Requiring a diagonal sudoku solution adds two more units to a sudoku puzzle, which further constrains the number of possible solutions.
This means that each time we identify a value for a box, this can further narrow down solutions for other boxes if that box is in one of the diagonal units.
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.