A little hobby project to solve the Sudoku I got stuck on during vacation. I know there are existing solutions out there, I just wanted to do it myself.

Execute in a terminal

pip3 install -r requirements.txt

Execute in a terminal

python3 -m main --input_file=assets/input/hard_input.json

The algorithm to solve the Sudoku is quite smart, in the sense that it doesn't just bruteforce all possibilities at random. It follows the rules of the game and never performs an action which would be illegal. First, it checks if it can figure out all cells for certain by using various strategies (see sudoku_solver.fill_certain_cells(...)). This will solve most Sudokus. If it's not yet solved, it will start guessing all possibilities for each cell, quitting if it's stuck. In the end, this should solve all Sudokus, even the hardest ones.