Write a program to solve easy Sudoku puzzles (where there is no ambiguity). This means that at any stage it is always possible to determine the value of an incomplete cell based only on the 3 rules for Sudoku puzzles.
How would this work in Python 3?

Question

Write a program to solve easy Sudoku puzzles (where there is no ambiguity). This means that at any stage it is always possible to determine the value of an incomplete cell based only on the 3 rules for Sudoku puzzles. 
How would this work in Python 3?

joachim · Answer

Write a program to solve easy Sudoku puzzles (where there is no ambiguity). This means that at any stage it is always possible to determine the value of an incomplete cell based only on the 3 rules for Sudoku puzzles.

Hints: Use an iterative algorithm where you continue to fill in obvious cells until the grid is complete. You can use a separate 2D array of lists to track the possible values for each cell as you scan through the grid each time. Whenever you encounter a list with only one possible value, this value can be chosen. Whenever you choose new values, update the possible value array by removing possibilities where applicable.

Sample input

059000483
000000012
010028000
098074020
040080030
070630540
000160050
620000000
735000860
Sample output

259716483
867345912
413928675
398574126
546281739
172639548
984163257
621857394
735492861