Q: How do we use constraint propagation to solve the naked twins problem?
A: Constraint Propagation applies constraints in a repeated manner in order to reduce the search space. Here we enforce the naked twins srategy which first identifies pairs of boxes belonging to the same set of peers - with the same 2 possible numbers - further eliminating from all boxes that also have these two boxes as peers.
We use the function naked_twins in conjunction with the eliminate and only-choice functions.
Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: Include the diagonals as an added unit, which will act as a constraint for all the boxes in the diagonals. This will remove possible digits from the unit's peers; these peers will include the diagonal, if the box is in a diagonal. It will not accept any solutions that do not satisfy this diagonal constraint.
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.