Q: How do we use constraint propagation to solve the naked twins problem?
A: My first approach was to find all the duplicates from the grid and then look for the twins in the grid. For each twin box, I was trying to remove the match character(character which were present in both peers and twins) from peers.
dups = dict()
for key, value in values.items():
if len(value) == 2:
if value not in dups:
dups[value] = [key]
else:
dups[value].append(key)
twins = dict()
for key,value in dups.items():
if len(value) == 2:
if not key in twins:
twins[key] = value
else:
twins[key].extend(value)
for key in twins:
for box in twins[key]:
print(peers[box])
for peer in peers[box]:
for key_element in list(key):
if values[peer] != key and len(values[peer])>=2:
assign_value(values, peer, values[peer].replace(key_element, ''))
But after looking the explaination on http://www.sudokudragon.com/tutorialnakedtwins.htm, I got to know my the fault in my approach. So, I changed my approach to remove matching character from either row_units and square units or column_units and square_units as twins will make impact on either row or column but not on both at the same time.
Q: How do we use constraint propagation to solve the diagonal sudoku problem?
A: I just create the diagonal units and add it to the unitlist. Units are being to used to create peers list to make sure that numbers are not repeated in any unit.
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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.
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