Starter File :

a5q1:

#a5q1 import node as node

def to_string(node_chain): """ Purpose: Create a string representation of the node chain. E.g., [ 1 | *-]-->[ 2 | *-]-->[ 3 | / ] Pre-conditions: :param node_chain: A node-chain, possibly empty Post_conditions: None Return: A string representation of the nodes. """ # special case: empty node chain if node_chain is None: result = 'EMPTY' else: # walk along the chain walker = node_chain value = node.get_data(walker) # print the data result = '[ ' + str(value) + ' |' while walker is not None: walker = node.get_next(walker) value = node.get_data(walker) # represent the next with an arrow-like figure result += ' *-]-->[ '+str(value)+' |'

# at the end of the chain, use '/' result += ' / ]'

return result

a5q2.py :

import node as node

def count_chain(node_chain): """ Purpose: Counts the number of nodes in the node chain. Pre-conditions: :param node_chain: a node chain, possibly empty Return: :return: The number of nodes in the node chain. """ return 0

def contains_duplicates(node_chain):

"""

Purpose:

Returns whether or not the given node_chain contains one or more duplicate data values.

Pre-conditions: :param node_chain: a node-chain, possibly empty Return:

:return: True if duplicate data value(s) were found,

False otherwise

""" return False

def insert_at(node_chain, value, index):

"""

Purpose:

Insert the given value into the node-chain so that

it appears at the the given index.

Pre-conditions: :param node_chain: a node-chain, possibly empty

:param value: a value to be inserted

:param index: the index where the new value should appear

Assumption: 0

where n is the number of nodes in the chain

Post-condition:

The node-chain is modified to include a new node at the

given index with the given value as data.

Return

:return: the node-chain with the new value in it

""" return None

a5q2-testing.py :

# test script

import a5q1 as a5q1 import a5q2 as a5q2 import node as node

#################################################################################################### #### UNIT TEST CASE: count_chain() #### args_in = None expected = 0 reason = 'Empty node chain'

result = a5q2.count_chain(args_in) if result != expected: print('Test failed: count_chain(): got', str(result), 'expected', str(expected), '--' + reason)

#### UNIT TEST CASE: count_chain() #### args_in = node.create(1) expected = 1 reason = 'node chain with one node'

result = a5q2.count_chain(args_in) if result != expected: print('Test failed: count_chain(): got', str(result), 'expected', str(expected), '--' + reason)

#### UNIT TEST CASE: count_chain() #### args_in = node.create(1, node.create('two')) expected = 2 reason = 'node chain with two nodes'

result = a5q2.count_chain(args_in) if result != expected: print('Test failed: count_chain(): got', str(result), 'expected', str(expected), '--' + reason)

#### UNIT TEST CASE: count_chain() #### args_in = node.create(1, node.create('two', node.create(3))) expected = 3 reason = 'node chain with three nodes'

result = a5q2.count_chain(args_in) if result != expected: print('Test failed: count_chain(): got', str(result), 'expected', str(expected), '--' + reason)

#################################################################################################### #### UNIT TEST CASE: contains_duplicates() #### args_in = None expected = False reason = 'Empty node chain'

result = a5q2.contains_duplicates(args_in) if result != expected: print('Test failed: contains_duplicates(): got', str(result), 'expected', str(expected), '--' + reason)

#### UNIT TEST CASE: contains_duplicates() #### args_in = node.create(1) expected = False reason = 'node chain with one node'

result = a5q2.contains_duplicates(args_in) if result != expected: print('Test failed: contains_duplicates(): got', str(result), 'expected', str(expected), '--' + reason)

#### UNIT TEST CASE: contains_duplicates() #### args_in = node.create('two', node.create('two')) expected = True reason = 'node chain with two nodes that are duplicates'

result = a5q2.contains_duplicates(args_in) if result != expected: print('Test failed: contains_duplicates(): got', str(result), 'expected', str(expected), '--' + reason)

#### UNIT TEST CASE: contains_duplicates() ####

Purpose: To practice working with node chains created using the Node ADT. Degree of Difficulty: Easy to Moderate In this question you'll write three functions for node-chains that are a little more challenging. On Moodle. you can find a starter fle called a5q2.py, with all the functions and doc-strings in place, and your job is to write the bodies of the functions You will also find a test script named a5q2 testing.py. It has a bunch of test cases pre-written foryou. Read it carefully! Use to_string() from Q1 to help you test and debug your functions. (a) (6 points) Implement the function count_chain). The interface for the function is: def count chain (node_chain): Purpose Counta the number of nodes in the node chain Pre conditions: :param node_chain: a node chain , pOSsibly empty Return: return: The number of nodes in the node chain Note carefully that the function is not to do any console output. A demonstration of the n of the function is as follows: empty_chain None chain node.create (1, node. create (2, node. create (3))) print'empty chain has', count_chain (empty-chain) elements') print ('chain has', count_chain (chain) 'elements) The output from the demonstration is as follows: empty chain has 0 elenents chain has 3 elenents (b) (6 points) Implement the function contains duplicatea). The interface for the function is: def contains_duplicates (node_chain): Purpose: Returns whether or not the given node_chain contains one or more duplicate data values Pre conditions: :param node_chain: a node - chain, possibly empty Return: return: True if duplicate data value (s) ere found, False otherwise For this question, you are NOT allowed to use a List to store data values, instead consider using two walkers and a nested loop. This operation should simply return True if we find ANY duplicate values, or False otherwise. Pseudocode for the algorithm follows on the next page. Purpose: To practice working with node chains created using the Node ADT. Degree of Difficulty: Easy to Moderate In this question you'll write three functions for node-chains that are a little more challenging. On Moodle. you can find a starter fle called a5q2.py, with all the functions and doc-strings in place, and your job is to write the bodies of the functions You will also find a test script named a5q2 testing.py. It has a bunch of test cases pre-written foryou. Read it carefully! Use to_string() from Q1 to help you test and debug your functions. (a) (6 points) Implement the function count_chain). The interface for the function is: def count chain (node_chain): Purpose Counta the number of nodes in the node chain Pre conditions: :param node_chain: a node chain , pOSsibly empty Return: return: The number of nodes in the node chain Note carefully that the function is not to do any console output. A demonstration of the n of the function is as follows: empty_chain None chain node.create (1, node. create (2, node. create (3))) print'empty chain has', count_chain (empty-chain) elements') print ('chain has', count_chain (chain) 'elements) The output from the demonstration is as follows: empty chain has 0 elenents chain has 3 elenents (b) (6 points) Implement the function contains duplicatea). The interface for the function is: def contains_duplicates (node_chain): Purpose: Returns whether or not the given node_chain contains one or more duplicate data values Pre conditions: :param node_chain: a node - chain, possibly empty Return: return: True if duplicate data value (s) ere found, False otherwise For this question, you are NOT allowed to use a List to store data values, instead consider using two walkers and a nested loop. This operation should simply return True if we find ANY duplicate values, or False otherwise. Pseudocode for the algorithm follows on the next page