Question 1

Which of the following operations from the array list data structure could be used in the implementation of the push and pop operations of a stack data structure?
I addLast
II addFirst
III removeLast

Accepted Answer

A)  I 
B)  II 
C)  I and III 
D)  II and III

Question 2

Assume that you have a hash table in which there are few or no collisions. What is the time required to add a new element to this hash table?

Accepted Answer

A)  O(log(n)) 
B)  O(n) 
C)  O(n2) 
D)  O(1)

Question 3

If we want a create a doubly-linked list data structure so that we can move from a node to the next node as well as to a previous node, we need to add a previous reference to the Node class. Each such DNode (doubly-linked Node) will have a data portion and two DNode references, next and previous. How many references need to be updated when we remove a node from the middle of such a list? Consider the neighboring nodes.

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4

Question 4

A doubly-linked list requires that each node maintain two references, one to the next node and one to the previous node. Which of the following statements about a doubly-linked list is NOT correct?

Accepted Answer

A)  If a node's next reference is null, it is at the end of the list. 
B)  To remove a node in the middle of the list, the previous node's next reference must be updated. 
C)  To add a node in the middle of the list, you must update the next reference of the node after which the new node will be added. 
D)  To remove a node in the middle of the list, the previous node's previous reference must be updated.

Question 5

Array list operations that were studied included adding/removing an element at the end or in the middle, and retrieving the kth element. Which of the following statements about these array list operations is correct?

Accepted Answer

A)  The least expensive operation of an array list is to add an element at the end. 
B)  The least expensive operation of an array list is to remove an element at the end. 
C)  The least expensive operation of an array list is to add an element in the middle. 
D)  The least expensive operation of an array list is to retrieve an arbitrary element.

Question 6

Using the textbook's implementation of a linked list, which of the following statements about changing the data stored in a previously visited element is correct?

Accepted Answer

A)  The node that will be updated is the most recently visited node. 
B)  The position.next reference must be updated when the data is updated. 
C)  The set method can be called again immediately after calling the add method. 
D)  The previous reference must be updated when the node is updated.

Question 7

Which of the following actions must be taken to add a node X at the end of a doubly-linked list?
I Update the next reference in the node before the position where X will be placed
II Update the previous reference in the node before the position where X will be placed
III Update the list's last reference

Accepted Answer

A)  I 
B)  II 
C)  I and II 
D)  I and III

Question 8

Adding or removing an arbitrary element in the middle of an array list takes ____ time.

Accepted Answer

A)  O(n) 
B)  O(1) 
C)  O(log(n)) 
D)  O(n2)

Question 9

You have implemented a queue as a singly-linked list, adding elements at the end and removing elements at the front. What is the cost of the add operation?

Accepted Answer

A)  O(log n) 
B)  O(n) 
C)  O(n2) 
D)  O(1)

Question 10

Which of the following algorithms would be efficiently executed on a LinkedList?

Accepted Answer

A)  tracking paths in a maze 
B)  binary search 
C)  remove first n / 2 elements from a list of n elements 
D)  read n / 2 elements in random order from a list of n elements

Question 11

Using the textbook's implementation of a linked list, what is the purpose of declaring the Node class to be a static inner class?

Accepted Answer

A)  To create an outer-class reference. 
B)  To create a this reference to itself. 
C)  To prevent storage of an outer-class reference that is not needed. 
D)  To create an outer-class reference that is needed.

Question 12

Suppose we maintain a linked list of length n in random element order. What would be the big-Oh notation for an algorithm that prints each list element and the number of times it occurs in the list (without sorting the list)?

Accepted Answer

A)  O(1) 
B)  O(n) 
C)  O(n log2 n) 
D)  O(n2)

Question 13

Which of the following statements about array list and doubly-linked list operations is correct?

Accepted Answer

A)  It is more efficient to add an element in the middle of an array list than a doubly-linked list. 
B)  It is more efficient to add an element to the beginning of an array list than a doubly-linked list. 
C)  It is more efficient to remove an element in the middle of an array list than a doubly-linked list. 
D)  It is more efficient to retrieve an element in the middle of an array list than a doubly-linked list.

Question 14

Assume that you have a hash table in which there are few or no collisions. What is the time required to remove an element from this hash table?

Accepted Answer

A)  O(n) 
B)  O(n2) 
C)  O(1) 
D)  O(log (n))

Question 15

Given the partial LinkedList class declaration below, select a statement to complete the size method, which is designed to return the number of list elements. public class LinkedList
{
Class Node
{
Public Object data;
Public Node next;
}
Private Node first;
) . .
Public int size()
{
Int count = 0;
Node temp = first;
While (temp != null)
{
Count++;
_____________________
}
Return count;
}
}

Accepted Answer

A)  temp = temp.next; 
B)  temp = first.next; 
C)  first = temp.next; 
D)  first = first.next;

Question 16

Given the LinkedListQueue class implementation discussed in section 16.3 (partially shown below), select the appropriate statements to complete the add method. public class LinkedListQueue
{
Private Node first;
Private Node last;
Public LinkedListQueue()
{
First = null;
Last = null;
}
Public void add(Object newElement)
{
Node newNode = new Node();
NewNode.data = newElement;
NewNode.next = null;
If (last == null)
{
First = newNode;
Last = newNode;
}
Else
{
_____________________
_____________________
}
}
)..
}

Accepted Answer

A)  last.next = newNode.next;
Last = newNode; 
B)  last.next = newNode;
Last = newNode; 
C)  last = newNode;
Last.next = newNode; 
D)  last = newNode;
Last.next = newNode.next;

Question 17

A stack can be implemented as a sequence of nodes in a linked list or an array list. Which of the following statements about this is correct?

Accepted Answer

A)  If implementing the stack as a linked list, the least expensive approach is to add and remove elements at the end. 
B)  If implementing the stack as an array list, the least expensive approach is to add and remove elements at the end. 
C)  If implementing the stack as an array list, there is no cost difference whether adding and removing elements at the beginning or the end. 
D)  If implementing the stack as a linked list, there is no cost difference whether adding and removing elements at the beginning or the end.

Question 18

What technique is used to store elements that hash to the same location?

Accepted Answer

A)  colliding 
B)  bucketing 
C)  deletion 
D)  sharing

Question 19

What type of access does the use of an iterator provide for the elements of a bucket in a hash table?

Accepted Answer

A)  sequential 
B)  semi-random 
C)  random 
D)  sorted

Question 20

In the open addressing technique for handling collisions in a hash table, ____.

Accepted Answer

A)  colliding elements are stored in a nested hash table. 
B)  colliding elements are placed in empty locations in the hash table. 
C)  colliding elements are stored in linked lists associated with the hash code. 
D)  the hash code is compressed to obtain unique hash codes.

Exam 16: Basic Data Structures

Which of the following operations from the array list data structure could be used in the implementation of the push and pop operations of a stack data structure? I addLast II addFirst III removeLast