board_solver.py

from config_validity_checker import currentconfig_isvalid
from empty_square_finder import find_empty


def solve(board):
    empty_sq = find_empty(board)
    if not empty_sq:
        return True, board
    else:
        row, col = empty_sq

    for i in range(1, 10):
        if currentconfig_isvalid(board, i, (row, col)):
            board[row][col] = i

            if solve(board)[0]:
                return True, board

            board[row][col] = 0

    return False, None


if __name__ == "__main__":
    test_board = [
        [0, 0, 0, 8, 0, 0, 4, 2, 0],
        [5, 0, 0, 6, 7, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 9, 0, 0, 5],
        [7, 4, 0, 1, 0, 0, 0, 0, 0],
        [0, 0, 9, 0, 3, 0, 7, 0, 0],
        [0, 0, 0, 0, 0, 7, 0, 4, 8],
        [8, 0, 0, 4, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 9, 8, 0, 0, 3],
        [0, 9, 5, 0, 0, 3, 0, 0, 0,],
    ]

    print(solve(test_board)[1])