Q: How do we use constraint propagation to solve the naked twins problem?
A: if there is a pair of boxes with identical values in a unit (row, column, diagonal) the values can be removed from the other boxes of the unit. The same reasoning can be applyed also for set of boxes > 2 e.g. tree boxes all with the same tree values.

Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: we use the constraint propagation in the same way as the non diagonal sudoku, the only difference is that the boxes on the main diagonal have more peers.

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 running python 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.