Instructions for the Script File

Define functions with the following names: load$\_$puzzle$(),$ display$\_$puzzle$(),$ get$\_$next$(),$ get$\_$options$(),$

copy$\_$puzzle$(),$and solve$().$ Descriptions of each of these functions are provided below.

load$\_$puzzle$()$

This function should accept a single parameter named path. This parameter is expected to be a string indicating the

path to a text file containing the initial state of a sudoku puzzle. The file will be expected to contain $9$ lines of text, each

of which contains $9$ numbers separated by spaces. The function should open the file and process the lines within. The

function should return a list of lists, with each sub$-$list containing the $9$ values on any one line of the file, stored as

integers.

The function should complete the desired task by performing the following steps:

$1.$ Use open$()$ and read$()$ to read in the contents of the file indicated by path as a string.

$2.$ Split the string from the previous step on the newline character, storing the result in a list named lines.

$3.$ Create an empty list named puzzle.

$4.$ Loop over the elements of lines. Perform the following steps for each string in lines:

a$.$ Split the string on spaces, storing the result in a list named token$\_$strings.

b$.$ Create a list named token$\_$ints that contains the values from token$\_$strings, but coerced to

integers. You can do this with a loop or a list comprehension.

c$.$ Append the list token$\_$ints to puzzle.

$5.$ Return puzzle.

display$\_$puzzle$()$

This function should accept a single parameter named puzzle. This parameter is expected to be a list of lists

representing a puzzle state. The function should print the puzzle state using the format displayed above on the right.

The function should complete the desired task by performing the following steps:

$1.$ Loop over the elements puzzle. Fir each list in puzzle, perform the following steps:

a$.$ If considering the list at index $0,3,$ or $6,$ print the following string: $\text{'}+-------+-------+-------+\text{'}$

b$.$ Create a string named row that is initially set equal to $\text{'}|\text{'}.$ We will concatenate values to this string to

build up the desired output for the current row.

c$.$ Loop over the elements of the current list, which will be int. For each int value, do the following:

i$.$ If the current value is zero, concatenate the string $\text{'}.\text{'}$ to row.

ii$.$ Otherwise, coerce the value to a string, and concatenate that and a space to row.

iii. If considering the element at index $2,5,$ or $8,$ concatenate the string $\text{'}|\text{'}$ to row.

d$.$ After the inner loop finishes, print row.

$2.$ After the outer loop finishes, print the bottom border of the puzzle: $\text{'}+-------+-------+-------+\text{'}$