Question 1

For a key value of 93 and a hashing function of key % 46 , what is the index into the array?

Accepted Answer

A)   1
B)   2
C)   46
D)   47E) A) and D)
F) A) and B)

Question 2

To reduce the probability of collisions with hashes, you can decrease the array length.

Accepted Answer

A) True 
 B)False

Question 3

Python supports multiple inheritance, so a class can have more than one parent class.

Accepted Answer

A) True 
 B)False

Question 4

Which of the following is a subset of Set A if Set A is {19 4 26 8}?

Accepted Answer

A)   None of the choices are subsets of Set A
B)   {19 4 26 8 0}
C)   {4 8 19 26 44}
D)   {}E) B) and C)
F) B) and D)

Question 5

Array-based implementations of sets and dictionaries do not perform well.

Accepted Answer

A) True 
 B)False

Question 6

Which method is specific to a set compared to a bag?

Accepted Answer

A)   remove
B)   __str__
C)   add
D)   __sub__E) C) and D)
F) B) and D)

Question 7

In the code for the __sub__ method for the AbstractSet class, what is the missing code? def __sub__(self, other) :
Difference = type(self) () 
For item in self:
If not item in other:

Return difference

Accepted Answer

A)   difference.remove(item) 
B)   intersection.add(item) 
C)   difference.add(item) 
D)   return(item) E) All of the above
F) C) and D)

Question 8

With a set, the difference and subset operations are not symmetric.

Accepted Answer

A) True 
 B)False

Question 9

A small load factor and an array length that is a prime number increases the chances for a hashing collision.

Accepted Answer

A) True 
 B)False

Question 10

In the hashing implementation of a set, self.index refers to the index of the chain in which the node was just located, or is -1 otherwise.

Accepted Answer

A) True 
 B)False  True

Question 11

In the implementation of the AbstractDict class, which four methods have the same implementation for all dictionaries?

Accepted Answer

A)   keys, values, __add__, __eq__
B)   entries, values, __init__, __str__
C)   keys, values, entries, get
D)   get, __add__, keys, __init__E) A) and D)
F) B) and D)

Question 12

In the code for the __init__ method in the Entry class or a dictionary, what is the missing code? def __init__(self, key, value) :

Self.value = value

Accepted Answer

A)   key = self.key
B)   self.key = key
C)   value = self.key
D)   self.key = valueE) A) and B)
F) C) and D)

Question 13

What is the performance value of the array-based implementations of sets and dictionaries?

Accepted Answer

A)   O( n 2) 
B)   O( n ) 
C)   O n 
D)   O(1) E) A) and D)
F) A) and C)

Question 14

A set is similar to a bag, but it contains unique data items and additional methods.

Accepted Answer

A) True 
 B)False

Question 15

The AbstractSet class is a subclass of AbstractBag .

Accepted Answer

A) True 
 B)False  False

Question 16

Referring to the keysToIndexes function, what is the result of the following statement? keysToIndexes([ 39, 18, 4, 51, 6, 28 ], 17)

Accepted Answer

A)   [ 6, 2, 5, 1, 7, 12 ]
B)   [ 7, 3, 6, 2, 8, 13 ]
C)   [ 4, 2, 3, 1, 5, 10 ]
D)   [ 5, 1, 4, 0, 6, 11 ]E) A) and C)
F) A) and D)

Question 17

In the code for the __iter__ method for the ArrayDict class, what is the missing code? def __iter__(self) :
Cursor = 0
While cursor

Accepted Answer

A)   return(self.items[ cursor ]) 
B)   cursor -= 1
C)   return(self.items[ key ]) 
D)   cursor += 1E) B) and C)
F) B) and D) D

Question 18

In the Entry class for a dictionary, comparisons are done using the value item in each entry.

Accepted Answer

A) True 
 B)False

Question 19

The standard Python hash function always returns a unique positive integer.

Accepted Answer

A) True 
 B)False

Question 20

In which collision-avoidance hashing strategy are the items stored in an array of linked lists in which each item's key locates the bucket where the item is to be inserted?

Accepted Answer

A)   clustering
B)   chaining
C)   quadratic probing
D)   linear probingE) All of the above
F) None of the above

Exam 11: Sets and Dictionaries

For a key value of 93 and a hashing function of key % 46 , what is the index into the array?

Correct AnswerverifiedShow Answer

To reduce the probability of collisions with hashes, you can decrease the array length.

Correct AnswerverifiedShow Answer

Python supports multiple inheritance, so a class can have more than one parent class.

Correct AnswerverifiedShow Answer

Which of the following is a subset of Set A if Set A is {19 4 26 8}?

Correct AnswerverifiedShow Answer

Array-based implementations of sets and dictionaries do not perform well.

Correct AnswerverifiedShow Answer

Which method is specific to a set compared to a bag?

Correct AnswerverifiedShow Answer

In the code for the __sub__ method for the AbstractSet class, what is the missing code? def __sub__(self, other) : Difference = type(self) () For item in self: If not item in other: < missing code > Return difference

Correct AnswerverifiedShow Answer

With a set, the difference and subset operations are not symmetric.

Correct AnswerverifiedShow Answer

A small load factor and an array length that is a prime number increases the chances for a hashing collision.

Correct AnswerverifiedShow Answer

In the hashing implementation of a set, self.index refers to the index of the chain in which the node was just located, or is -1 otherwise.

Correct AnswerverifiedTrue

In the implementation of the AbstractDict class, which four methods have the same implementation for all dictionaries?

Correct AnswerverifiedShow Answer

In the code for the __init__ method in the Entry class or a dictionary, what is the missing code? def __init__(self, key, value) : < missing code > Self.value = value

Correct AnswerverifiedShow Answer

What is the performance value of the array-based implementations of sets and dictionaries?

Correct AnswerverifiedShow Answer

A set is similar to a bag, but it contains unique data items and additional methods.

Correct AnswerverifiedShow Answer

The AbstractSet class is a subclass of AbstractBag .

Correct AnswerverifiedFalse

Referring to the keysToIndexes function, what is the result of the following statement? keysToIndexes([ 39, 18, 4, 51, 6, 28 ], 17)

Correct AnswerverifiedShow Answer

In the code for the __iter__ method for the ArrayDict class, what is the missing code? def __iter__(self) : Cursor = 0 While cursor < len(self) : Yield self.items[cursor].key < missing code >

Correct AnswerverifiedD

In the Entry class for a dictionary, comparisons are done using the value item in each entry.

Correct AnswerverifiedShow Answer

The standard Python hash function always returns a unique positive integer.

Correct AnswerverifiedShow Answer

In which collision-avoidance hashing strategy are the items stored in an array of linked lists in which each item's key locates the bucket where the item is to be inserted?

Correct AnswerverifiedShow Answer

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In the code for the sub method for the AbstractSet class, what is the missing code? def sub(self, other) : Difference = type(self) () For item in self: If not item in other: < missing code > Return difference

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True

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In the code for the init method in the Entry class or a dictionary, what is the missing code? def init(self, key, value) : < missing code > Self.value = value

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False

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In the code for the iter method for the ArrayDict class, what is the missing code? def iter(self) : Cursor = 0 While cursor < len(self) : Yield self.items[cursor].key < missing code >

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D

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