# CptS355 – Assignment 3 dictionary stores solution

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## Description

Problems:
1. all_games(wsu_games) – 8%
The following dictionary stores WSU’s college football game scores for the past 4 years. In 2020, WSU
played only 4 games due to pandemic.
Assume, you would like to rearrange this data and create a dictionary where the keys are the opponent
teams and the values are dictionaries of games WSU played against those teams, e.g.,
Write a function all_games that takes the WSU’s game data as input and rearranges keys as described
above. You may use loops in your solution. The items in the output dictionary can have arbitrary order.
all_games(wsu_games) returns the above dictionary.
Important Notes:
1. Your function should not change the input dictionary value.
2. You should not hardcode the keys (years and opponent team names) in your solution.
wsu_games = {
2018: { “WYO”:(41,19), “SJSU”:(31,0), “EWU”:(59,24), “USC”:(36,39), “UTAH”:(28,24),
“ORST”:(56,37), “ORE”:(34,20), “STAN”:(41,38), “CAL”:(19,13), “COLO”:(31,7),
“ARIZ”:(69,28), “WASH”:(15,28), “ISU”:(28,26)},
2019: {“NMSU”:(58,7), “UNCO”:(59,17), “HOU”:(31,24), “UCLA”:(63,67), “UTAH”:(13,38),
“ASU”:(34,38), “COLO”:(41,10), “ORE”:(35,37), “CAL”:(20,33), “STAN”:(49,22),
“ORST”:(54,53), “WASH”:(13,31), “AFA”:(21,31) },
2020: {“ORST”:(38,28), “ORE”:(29,43), “USC”:(13,38), “UTAH”:(28,45)},
2021: { “USU”:(23,26), “PORT ST.”:(44,24), “USC”:(14,45), “UTAH”:(13,24), “CAL”:(21,6),
“ORST”:(31,24), “STAN”:(34,31), “BYU”:(19,21), “ASU”:(34,21), “ORE”:(24,38),
“ARIZ”:(44,18), “WASH”:(40,13), “CMU”:(21,24)} }
{ ‘WYO’: {2018: (41, 19)},
‘SJSU’: {2018: (31, 0)},
‘EWU’: {2018: (59, 24)},
‘USC’: {2018: (36, 39), 2020: (13, 38), 2021: (14, 45)},
‘UTAH’: {2018: (28, 24), 2019: (13, 38), 2020: (28, 45), 2021: (13, 24)},
‘ORST’: {2018: (56, 37), 2019: (54, 53), 2020: (38, 28), 2021: (31, 24)},
‘ORE’: {2018: (34, 20), 2019: (35, 37), 2020: (29, 43), 2021: (24, 38)},
‘STAN’: {2018: (41, 38), 2019: (49, 22), 2021: (34, 31)},
‘CAL’: {2018: (19, 13), 2019: (20, 33), 2021: (21, 6)},
‘COLO’: {2018: (31, 7), 2019: (41, 10)},
‘ARIZ’: {2018: (69, 28), 2021: (44, 18)},
‘WASH’: {2018: (15, 28), 2019: (13, 31), 2021: (40, 13)},
‘ISU’: {2018: (28, 26)},
‘NMSU’: {2019: (58, 7)},
‘UNCO’: {2019: (59, 17)},
‘HOU’: {2019: (31, 24)},
‘UCLA’: {2019: (63, 67)},
‘ASU’: {2019: (34, 38), 2021: (34, 21)},
‘AFA’: {2019: (21, 31)},
‘USU’: {2021: (23, 26)},
‘PORT ST.’: {2021: (44, 24)},
‘BYU’: {2021: (19, 21)},
‘CMU’: {2021: (21, 24)} }
2. common_teams(wsu_games)– 15%
Now consider that you would like to find the teams WSU played with every year – for the years included in
wsu_games data. Write a function common_teams that parses through the WSU game data and finds the
teams that appear in every year’s games. The function should return a dictionary where the keys are the
team names and the values are the list of scores against those teams.
For example:
common_teams(wsu_games) returns
{‘UTAH’: [(28, 24), (13, 38), (28, 45), (13, 24)],
‘ORST’: [(56, 37), (54, 53), (38, 28), (31, 24)],
‘ORE’: [(34, 20), (35, 37), (29, 43), (24, 38)]}
WSU played with ‘UTAH’,’ORST’ and,’ORE’ in all 4 years.
Important Note:
– You are not allowed to use Python libraries we haven’t covered in class in your solution.
– Your function should not change the input dictionary value.
– You should not hardcode the keys (years and opponent team names) in your solution.
3. get_wins(wsu_games, team)– 16%
Assume you would like to find the scores for the games WSU won against a given team. Write a function
“get_wins” that takes the WSU game data and a team name as input, and it returns a list of tuples that
includes the years and scores of each game WSU played and won against that team. For example,
get_wins(wsu_games,’UTAH’) returns [(2018, (28, 24))]
#WSU played 4 games with ‘UTAH’ but won only the 2018 game
get_wins(wsu_games,’STAN’) returns
[(2018, (41, 38)), (2019, (49, 22)), (2021, (34, 31))]
#WSU played 3 games with ‘STAN’ and won all 3 games
Your function definition should not use loops or recursion but use the Python map, reduce, and/or
filter functions. You may define and call helper (or anonymous) functions, however your helper
functions should not use loops or recursion. You cannot use all_games function you defined in problem 1.
You will not get any points if your solution (or helper functions) uses a loop. If you are using reduce, make
sure to import it from functools.
4. wins_by_year(wsu_games)– 16%
Assume you would like to find the number of games WSU won each year. Write a function
“wins_by_year” that takes the WSU game data as input, and it returns a list of tuples where each tuple
includes the year and the number wins during that year. For example,
wins_by_year(wsu_games) returns [(2018, 11), (2019, 6), (2020, 1), (2021, 7)]
# WSU won 11, 6, 1, and 7 games in 2018, 2019, 2020, and 2021, respectively.
Your function definition should not use loops or recursion but use the Python map, reduce, and/or
filter functions. You may define and call helper (or anonymous) functions, however your helper
functions should not use loops or recursion. You cannot use all_games function you defined in problem 1.
You will not get any points if your solution (or helper functions) uses a loop. If you are using reduce, make
sure to import it from functools.
5. max_path(graph,node)– 16%
Consider the following directed graph where each node has zero or more outgoing edges. Assume the
graph nodes are assigned unique labels. This graph can be represented as a Python dictionary where the
keys are the starting nodes of the edges and the values are the set of the ending nodes (represented as
Python sets). Note that some nodes in the graph are halting nodes, i.e., they don’t have any outgoing
edges. Those nodes are marked with double lines in the graph.
{‘A’:{‘B’,’C’,’D’},’B’:{‘C’},’C’:{‘B’,’E’,’F’,’G’},’D’:{‘A’,’E’,’F’},’E’:{‘F’},
‘F’:{‘E’, ‘G’},’G’:{}, ‘H’:{‘F’,’G’}}
Write a function, longest_path, which takes a graph dictionary (similar to the above) and a node label as
input and returns the length of the longest path (without any cycles) from the given node to a halting node
in the graph. For example, longest_path(graph,’A’) will return 6, since the longest path from ‘A’ to a
halting node ‘G’ – without cycles – goes through 6 nodes, including the node ‘A’ and ‘G’, i.e., [‘A’,
‘B’, ‘C’, ‘E’, ‘F’,’G’].
You may use recursion and/or loops in your solution.
graph = {‘A’:{‘B’,’C’,’D’}, ‘B’:{‘C’}, ‘C’:{‘B’,’E’,’F’,’G’}, ‘D’:{‘A’,’E’,’F’},
‘E’:{‘F’}, ‘F’:{‘E’, ‘G’}, ‘G’:{}, ‘H’:{‘F’,’G’}}
longest_path(graph,’A’) returns 6 , i.e., [‘A’, ‘B’, ‘C’, ‘E’, ‘F’,’G’]
longest_path(graph,’D’) returns 7 , i.e., [‘D’, ‘A’, ‘B’, ‘C’, ‘E’, ‘F’,’G’]
longest_path(graph,’C’) returns 4 , i.e., [‘C’, ‘E’, ‘F’,’G’]
longest_path(graph,’F’) returns 2 , i.e., [‘F’,’G’]
A B C
D
F
G
E
H
6. Iterators
counter()– 20%
Create an iterator that represents the sequence of words and from a string input. The iterator is initialized
with the input string. At each call to __next__(),the iterator will return the next word and the number
of times we have seen that word **so far** in the form of a tuple. The first occurrence of each word will
have count 1.
The iterator should ignore all extra spaces, empty lines, and end of line characters, i.e., ‘\n’ .
Important Note: Your counter implementation should extract the words from the input text as needed.
An implementation that splits the complete string and dumps all words to a list all at once will be worth
only 5 points.
For example:
numbers = “””
one
one two
one two three
one two three four
one two three four five
one two three four five six
“””
rest = []
mywords = counter(numbers)
mywords.__next__() # skip over first 2 words
mywords.__next__()
for word in mywords:
rest.append(word)
rest will be :
[(‘two’, 1), (‘one’, 3), (‘two’, 2), (‘three’, 1), (‘one’, 4), (‘two’, 3),
(‘three’, 2), (‘four’, 1), (‘one’, 5), (‘two’, 4), (‘three’, 3), (‘four’, 2),
(‘five’, 1), (‘one’, 6), (‘two’, 5), (‘three’, 4), (‘four’, 3), (‘five’, 2),
(‘six’, 1)]
Assignment rules – 3%
Make sure that your assignment submission complies with the following. :
– Make sure that all your debugging print statements are removed or disabled. When we run the tests,
only the unittest output should be displayed.
– Make sure to include your own tests in HW2tests.py file.
We will be using the unittest Python testing framework in this assignment. See