chapter15

102) Which data structure would best be used for keeping track of bank customers waiting for a teller? a) queue b) stack c) list d) array

a

16) A linear search only requires ____ access. a) sequential b) random c) sorted d) arbitrary

a

92) Which data structure would best be used for finding a path out of a maze? a) queue b) stack c) list d) array

b

40) You use a(n) ____ to access elements inside a linked list. a) accessor b) index c) list iterator d) queue

c

87) Assume that you have declared a stack named myStack to hold String elements. Which of the following statements will correctly add an element to myStack? a) myStack.put("apple"); b) myStack.addItem("apple"); c) myStack.push("apple"); d) myStack.insert("apple");

c

108) Which of the following statements about a priority queue structure is NOT correct? a) Elements added to a priority queue must belong to a class that implements the Comparable interface. b) New elements can be inserted in any order. c) The remove method is used to remove an element from the priority queue. d) The insert method is used to add a new element to the priority queue.

d

79) You need to write a program to build and maintain an address book. Since the program must support the possibility of having duplicate names, which data structure would be most appropriate to model this situation? a) map b) stack c) queue d) linked list

d

68) You want to enumerate all of the keys in a map named myMap whose keys are type String. Which of the following statements will allow you to do this? a) Set<String> keySet = myMap.keySet(); for (String key : keySet) {. . . } b) Set<String> keySet = myMap.getKeys(); for (String key : keySet) {. . . } c) Set<String> keySet = myMap.keys(); for (String key : keySet) {. . . } d) Set<String> keySet = myMap.getKeySet(

a

49) Which of the following statements about the TreeSet class is NOT correct? a) Elements are stored in sorted order. b) Elements are arranged in linear fashion. c) Elements are stored in nodes. d) To use a TreeSet, it must be possible to compare the elements.

b

52) To create a TreeSet for a class of objects, the object class must ____. a) create an iterator. b) implement the Comparable interface. c) implement the Set interface. d) create a Comparator object.

b

56) Assume that you have declared a set named mySet to hold String elements. Which of the following statements will correctly remove an element from mySet? a) mySet.get("apple"); b) mySet.remove("apple"); c) mySet.pop("apple"); d) mySet.delete("apple");

b

48) Which of the following statements about hash tables is NOT correct? a) Elements are grouped into smaller collections that share the same characteristic. b) You can form hash tables holding objects of type String. c) You can add an element to a specific position within a hash table. d) The value used to locate an element in a hash table is called a hash code.

c

50) Select an appropriate declaration to complete the following code segment, which is designed to read strings from standard input and display them in increasing alphabetical order, excluding any duplicates. _________________________________________ Scanner input = new Scanner(System.in); while (input.hasNext()) { words.add(input.next()); } System.out.print(words); a) LinkedList<String> words = new LinkedList<String>(); b) Set<String> words = new Set<String>(); c) Set<String> words = new HashSet<String>(); d) Set<String> words = new TreeSet<String>();

d

53) Which of the following statements about manipulating objects in a set is correct? a) If you try to add an element that already exists, an exception will occur. b) If you try to remove an element that does not exist, an exception will occur. c) You can add an element at the position indicated by an iterator. d) A set iterator visits elements in the order in which the set implementation keeps them.

d

54) Which of the following statements about manipulating objects in a set is correct? a) If you try to add an element that already exists, an exception will occur. b) A set iterator visits elements in the order in which they were added to the set. c) You can add an element at the position indicated by an iterator. d) You can remove an element at the position indicated by an iterator.

d

19) What type of access does a LinkedList provide for its elements? a) sequential b) semi-random c) random d) sorted

a

2) A list is a collection that ____. a) should be used when you need to remember the order of elements in the collection. b) allows items to be added at one end and removed at the other end. c) does not allow elements to be inserted in any position. d) manages associations between keys and values.

a

25) Assume you have created a linked list named myList that currently holds some number of String objects. Which of the following statements correctly adds a new element to the beginning of myList? a) myList.addFirst("Harry"); b) myList.add("Harry"); c) myList.insert("Harry"); d) myList.put("Harry");

a

29) Which method is NOT part of the ListIterator interface? a) delete b) add c) next d) previous

a

3) A stack is a collection that ____. a) remembers the order of elements, and allows elements to be added and removed only at one end. b) does not remember the order of elements but allows elements to be added in any position. c) remembers the order of elements and allows elements to be inserted in any position. d) remembers the order of elements and allows elements to be inserted only at one end and removed only at the other end.

a

33) Select an appropriate expression to complete the method below. The method should return the number of times that the string stored in name appears in theList. public static int count(LinkedList<String> theList, String name) { int number = 0; Iterator<String> iter = theList.iterator(); while (______________________) { if (iter.next().equals(name)) { number++; } } return number; } a) iter.hasNext() b) iter.next() != null c) theList.hasNext() d) theList.next() != null

a

37) Which of the following statements about the LinkedList class is correct? a) When you use the add method, the new element is inserted before the iterator, and the iterator position is advanced by one position. b) When you use the add method, the new element is inserted after the iterator, and the iterator position is advanced by one position. c) When you use the add method, the new element is inserted before the iterator, and the iterator position is not moved d) When you use the add method, the new element is inserted after the iterator, and the iterator position is not moved.

a

38) When using a list iterator, on which condition will the NoSuchElementException be thrown? a) Calling next when you are past the end of the list. b) Calling next when the iterator points to the last element. c) Calling remove after calling add. d) Calling remove after calling previous.

a

41) A linked list allows ____ access, but you need to ask the list for an iterator. a) sequential b) random c) sorted d) arbitrary

a

58) Which of the following statements about manipulating objects in a map is NOT correct? a) Use the add method to add a new element to the map. b) Use the get method to retrieve a value from the map. c) Use the keyset method to get the set of keys for the map. d) Use the remove method to remove a value from the map.

a

60) Complete the following code, which is intended to print out all key/value pairs in a map named myMap that contains String data for student IDs and names: Map<String, String> myMap = new HashMap<String, String>(); . . . Set<String> mapKeySet = myMap.keySet(); for (String aKey : mapKeySet) { ___________________________; System.out.println("ID: " + aKey + "->" + name); } a) String name = myMap.get(aKey); b) String name = myMap.next(aKey); c) String name = MapKeySet.get(aKey); d) String name = MapKeySet.next(aKey);

a

67) Consider the following code snippet: Map<String, Integer> scores; You expect to retrieve elements randomly by key, and want fastest retrieval times. Which of the following statements will create a structure to support this? a) scores = new HashMap<String, Integer>; b) scores = new TreeMap<String, Integer>; c) scores = new Map<String, Integer>; d) scores = new TreeSet<String, Integer>;

a

70) You need to access values in objects by a key that is not part of the object. Which collection type should you use? a) Map b) Hashtable c) ArrayList d) Queue

a

73) You need to access values using a key, and the keys must be sorted. Which collection type should you use? a) TreeMap b) ArrayList c) HashMap d) Queue

a

8) A collection that allows speedy insertion and removal of already-located elements in the middle of it is called a ____. a) linked list b) stack c) set d) queue

a

80) You need to write a program to build and maintain a catalog of college courses that are associated with specific majors. Which data structure would be most appropriate to model this situation? a) map b) stack c) queue d) linked list

a

83) Which of the following statements about hash functions is NOT correct? a) A hash function produces a unique integer-valued hash code value for each distinct object. b) A good hash function will minimize the number of objects that are assigned the same hash code. c) Using a prime number as a hash multiplier will produce better hash codes. d) If you supply your own hashCode method for a class, it must be compatible with that class's equals method.

a

86) Which of the following correctly declares a stack that will hold String elements? a) Stack<String> s = new Stack<String>(); b) Stack s = new Stack<String>(); c) String s = new Stack<String>(); d) String s = new Stack();

a

90) Consider the code snippet shown below: Stack<String> words1 = new Stack<String>(); Stack<String> words2 = new Stack<String>(); words1.push("abc"); words1.push("def"); words1.push("ghi"); while (!words1.empty()) { words2.push(words1.pop()); } while (!words2.empty()) { System.out.print(words2.pop()); } What will be printed when this code is executed? a) abcdefghi b) ghiabcdef c) abcghidef d) defghiabc

a

91) Consider the following code snippet: Stack<String> words1 = new Stack<String>(); ArrayList<String> words3 = new ArrayList<String>(); words1.push("abc"); words1.push("def"); words1.push("ghi"); while (!words1.empty()) { words3.add(words1.pop()); } int i = words3.size() - 1; while (i >= 0) { System.out.print(words3.remove(i)); i--; } What will this code print when it is executed? a) abcdefghi b) ghiabcdef c) abcghidef d) defghiabc

a

96) Assume that you have declared a queue named myQueue to hold String elements. Which of the following statements will correctly remove an element from myQueue? a) myQueue.remove(); b) myQueue.get(); c) myQueue.delete(); d) myQueue.pop();

a

99) Assuming that names is a Queue of String objects, select a statement to complete the code segment below. The code is designed to remove the last element from the queue, which is guaranteed to have at least one element. Queue<String> aQueue = new LinkedList<String>(); while (names.size() > 1) { aQueue.add(names.remove()); } names.remove(); while (aQueue.size() > 0) { ____________________________ } a) names.add(aQueue.remove()); b) names.add(aQueue.peek()); c) aQueue.add(names.remove()); d) aQueue.add(names.peek());

a

10) Select an appropriate expression to complete the following code segment, which is designed to print a message if the string stored in name is part of the players collection. Collection<String> players = new ArrayList<String>(); // code to add elements to the collection here if ______________________________________ System.out.print(name + " is one of the players in the collection."); a) (players.indexOf(name)) b) (players.contains(name)) c) (players.search(name)) d) (players.equals(name))

b

14) Which nodes need to be updated when we insert a new node to become the fourth node from the beginning of a doubly-linked list? a) The current third node. b) The current third and fourth nodes. c) The current first node. d) The current fourth and fifth nodes.

b

17) Rather than storing values in an array, a linked list uses a sequence of ____. a) indexes b) nodes c) elements d) accessors

b

20) Consider the following code snippet: LinkedList<String> words = new LinkedList<String>(); words.addLast("abc"); words.addLast("def"); words.addLast("ghi"); System.out.print(words.removeLast()); System.out.print(words.removeFirst()); System.out.print(words.removeLast()); What will this code print when it is executed? a) abcdefghi b) ghiabcdef c) abcghidef d) defghiabc

b

22) The term ____ is used in computer science to describe an access pattern in which the elements are accessed in arbitrary order. a) sequential access b) random access c) sorted access d) arbitrary access

b

23) Which Java package contains the LinkedList class? a) java.lang b) java.util c) java.collections d) java.io

b

26) Assume you have created a linked list name myList that currently holds some number of String objects. Which of the following statements correctly removes an element from the end of myList? a) myList.remove(); b) myList.removeLast(); c) myList.getLast(); d) myList.pop();

b

30) Consider the code snippet shown below. Assume that employeeNames is an instance of type LinkedList<String>. for (String name : employeeNames) { // Do something with name here } Which element(s) of employeeNames does this loop process? a) no elements b) all elements c) elements meeting a condition d) the most recently added elements

b

31) Which method is NOT part of the ListIterator generic class? a) hasNext b) hasMore c) hasPrevious d) add

b

43) Assume you are using a doubly-linked list data structure with many nodes. What is the minimum number of node references that are required to be modified to remove a node from the middle of the list? Consider the neighboring nodes. a) 1 b) 2 c) 3 d) 4

b

61) Assume that you have declared a map named myMap to hold String elements with Integer keys. Which of the following statements will correctly insert an element into myMap? a) myMap.insert(3, "apple"); b) myMap.put(3, "apple"); c) myMap.push(3, "apple"); d) myMap.add(3, "apple");

b

62) Assume that you have declared a map named myMap to hold String elements with Integer keys. Which of the following statements will correctly remove an element from myMap? a) myMap.get(3); b) myMap.remove(3); c) myMap.pop(3); d) myMap.delete(3);

b

65) Which of the following statements about manipulating objects in a map is NOT correct? a) If you attempt to retrieve a value with a key that is not associated with any value, you will receive a null result. b) You cannot change the value of an existing association in the map; you must delete it and re-add it with the new values. c) Use the get method to retrieve a value associated with a key in the map. d) Use the put method to add an element to the map.

b

66) Consider the following code snippet: Map<String, Integer> scores; If you need to visit the keys in sorted order, which of the following statements will create a structure to support this? a) scores = new HashMap<String, Integer>; b) scores = new TreeMap<String, Integer>; c) scores = new Map<String, Integer>; d) scores = new HashTable<String, Integer>;

b

7) A collection that remembers the order of items, and allows items to be added and removed only at one end is called a ____. a) list b) stack c) set d) queue

b

74) You have decided to store objects of a class in a TreeSet structure. Which of the following statements is correct? a) If the object class implements the Comparable interface, and the sort order in the compare method is acceptable, you do not have to do anything else. b) If the object class implements the Comparable interface, and the sort order in the compareTo method is acceptable, you do not have to do anything else. c) If the object class implements the Comparable interface, and the sort order in the compare method is acceptable, you must create a comparator object. d) If the object class implements the Comparable interface, and the sort order in the compareTo method is acceptable, you must create a comparator object.

b

What output will be produced when this code is executed? a) ab,abc,a, b) a,abc,ab, c) a,ab,abc, d) abc,ab,a,

b

1) The ArrayList class implements the ____. a) Queue interface. b) Set interface. c) List interface. d) Stack interface

c

100) Select an appropriate expression to complete the following method, which is designed to return the sum of the two smallest values in the parameter array numbers. public static int sumTwoLowestElements(int[] numbers) { PriorityQueue<Integer> values = new PriorityQueue<Integer>(); for (int num: numbers) { values.add(num); } ______________________ } a) return values.peek() + values.peek(); b) return values.peek() + values.remove(); c) return values.remove() + values.remove(); d) return values.remove() * 2;

c

101) Suppose you push integer elements 1,2,3,4 onto a stack in that order. Then pop an element off the stack and add that element to a queue. You repeat that process three more times. In what order will you remove the elements from the queue? a) 1,2,3,4 b) 1,2,4,3 c) 4,3,2,1 d) 4,3,1,2

c

103) Suppose we have two String objects and treat the characters in each string from beginning to end in the following way: With one string, we push each character on a stack. With the other string, we add each character to a queue. After processing both strings, we then pop one character from the stack and remove one character from the queue, and compare the pair of characters to each other. We do this until the stack and the queue are both empty. What does it mean if all the character pairs match? a) The strings are the identical. b) The strings are different. c) One string is the reverse of the other. d) We can only conclude the strings are of the same length

c

107) Which of the following statements about a priority queue structure is correct? a) It uses a FIFO discipline. b) New items must be inserted at the end of the queue. c) Elements must be removed in priority order. d) It uses a LIFO discipline.

c

109) Consider the following code snippet: PriorityQueue<String> stringQueue = new PriorityQueue<String>(); stringQueue.add("ab"); stringQueue.add("abc"); stringQueue.add("a"); while (stringQueue.size() > 0) { System.out.print(stringQueue.remove() + ","); } What output will be produced when this code is executed? a) ab,abc,a, b) a,abc,ab, c) a,ab,abc, d) abc,ab,a,

c

18) Which of the following algorithms would be efficiently executed using a LinkedList? 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.

c

24) What can a generic class be parameterized for? a) properties b) iterators c) type d) methods

c

27) A(n) ____ is a data structure used for collecting a sequence of objects that allows efficient addition and removal of alreadylocated elements in the middle of the sequence. a) stack b) queue c) linked list d) priority queue

c

28) What is the meaning of the type parameter E, in the LinkedList<E> code fragment? a) The elements of the linked list are of class E. b) The elements of the linked list are of any subclass of class E. c) The elements of the linked list are any type supplied to the constructor. d) The elements of the linked list are of class Object.

c

32) Select an appropriate expression to complete the following code segment, which is designed to print a message if the string stored in name is the first element of the players linked list. LinkedList<String> players = new LinkedList<String>(); // code to add elements to the linked list if ______________________________________ System.out.print(name + " is the first player on the list."); a) (players.indexOf(name) == 1) b) (players.contains(name)) c) (players.getFirst().equals(name)) d) (players[0].equals(name))

c

35) When using a list iterator, on which condition will the IllegalStateException be thrown? a) Calling remove after calling next. b) Calling next after calling previous. c) Calling remove after calling remove. d) Calling remove after calling previous.

c

36) When using a list iterator, on which condition will the IllegalStateException be thrown? a) Calling remove after calling next. b) Calling add after calling previous. c) Calling remove after calling add. d) Calling previous after calling previous.

c

42) The nodes of a(n) ____ linked list class store two links: one to the next element and one to the previous one. a) array b) singly c) doubly d) randomly

c

44) In a linked list data structure, when does the reference to the first node need to be updated? I inserting into an empty list II deleting from a list with one node III deleting an inner node a) I b) II c) I and II d) III

c

46) Which of the following statements about data structures is correct? a) Inserting and removing elements that have already been located is faster with a list than with a set. b) Accessing elements in a linked list in a random fashion is efficient. c) Adding and removing already-located elements in the middle of a linked list is efficient.

c

51) Select an appropriate expression to complete the following method, which is designed to return the number of elements in the parameter array numbers. If a value appears more than once, it should be counted exactly once. public static int countElementsOnce(int[] numbers) { Set<Integer> values = new HashSet<Integer>(); for (int num: numbers) { values.add(num); } ______________________ } a) return numbers.length; b) return values.length(); c) return values.size(); d) return numbers.length - values.size();

c

63) Assume that you have declared a map named myMap to hold String elements with Integer keys. Which of the following statements will correctly retrieve the value of an element from myMap by using its key? a) myMap.get("apple"); b) myMap.peek("apple"); c) myMap.get(3); d) myMap.peek(3);

c

69) You need to access values by an integer position. Which collection type should you use? a) Map b) Hashtable c) ArrayList d) Queue

c

72) You need to access values in the opposite order in which they were added (last in, first out), and not randomly. Which collection type should you use? a) Map b) Hashtable c) Stack d) Queue

c

78) You need to write a program to simulate the effect of adding an additional cashier in a supermarket to reduce the length of time customers must wait to check out. Which data structure would be most appropriate to simulate the waiting customers? a) map b) stack c) queue d) linked list

c

81) You need to write a program to manage a waiting list of patrons at a restaurant. Which data structure would be most appropriate to model this situation? a) map b) stack c) queue d) linked list

c

84) Which of the following statements about stacks is correct? a) A stack implements first-in, first-out retrieval. b) A stack implements random retrieval. c) A stack implements last-in, first-out retrieval. d) A stack stores elements in sorted order.

c

85) An Undo feature in a word processor program that allows you to reverse a previously completed command is probably implemented using which structure type? a) queue b) linked list c) stack d) hash table

c

9) Which data structure would best be used for keeping track of a growing set of groceries to be purchased at the food market? a) queue b) stack c) list d) array

c

98) Select an appropriate expression to complete the method below, which is designed to print the element at the bottom of a Stack collection. The contents of the original stack are restored before the method terminates. It is safe to assume that the original stack contains at least one element. public static void printBottom(Stack<String> theStack) { Stack<String> anotherStack = new Stack<String>(); while (theStack.size() > 0) { anotherStack.push(theStack.pop()); } ____________________________ while (anotherStack.size() > 0) { theStack.push(anotherStack.pop()); } } a) System.out.println(theStack.pop()); b) System.out.println(theStack.peek()); c) System.out.println(anotherStack.peek()); d) System.out.println(anotherStack.pop());

c

What will be printed when this code is executed? a) [Mary, John, Robert, Sue] b) [Mary, John, Sue] c) [Mary, Robert, Sue] d) [John, Robert, Sue]

c

11) What is included in a linked list node? I a reference to its neighboring nodes II an array reference III a data element a) I b) II c) II and III d) I and III

d

21) Consider the following code snippet: LinkedList<String> words = new LinkedList<String>(); words.addFirst("abc"); words.addLast("def"); words.addFirst("ghi"); System.out.print(words.removeLast()); System.out.print(words.removeFirst()); System.out.print(words.removeLast()); What will this code print when it is executed? a) abcdefghi b) ghiabcdef c) abcghidef d) defghiabc

d

34) Select an appropriate expression to complete the following method, which is designed to visit the elements in theList and replace each occurrence of the string "hello" with the string "goodbye". public static void helloGoodbye(LinkedList<String> theList) { ListIterator<String> iterator = theList.listIterator(); while (iterator.hasNext()) { if (iterator.next().equals("hello")) { _____________________________ } } } a) iterator.replace("hello", "goodbye"); b) iterator.next() = "goodbye"; c) iterator.previous("goodbye"); d) iterator.set("goodbye");

d

39) A linked list ____ encapsulates a position anywhere inside the linked list. a) accessor b) index c) operation d) iterator

d

4) A queue is a collection that ____. a) remembers the order of elements, and allows elements to be added and removed only at one end. b) does not remember the order of elements but allows elements to be added in any position. c) remembers the order of elements and allows elements to be inserted in any position. d) remembers the order of elements and allows elements to be inserted only at one end and removed only at the other end

d

47) Which of the following statements about sets is correct? a) Inserting and removing elements that have already been located is faster with a list than with a set. b) A set allows duplicate values. c) You can add an element to a specific position within a set. d) A set is a collection of unique elements organized for efficiency.

d

59) Complete the following code, which is intended to print out all key/value pairs in a map named myMap that contains String data for student IDs and names: Map<String, String> myMap = new HashMap<String, String>(); . . . _______________________________ for (String aKey : mapKeySet) { String name = myMap.get(aKey); System.out.println("ID: " + aKey + "->" + name); Maha Otaibi 112 } a) Map<String, String> mapKeySet = myMap.keySet(); b) Set<String, String> mapKeySet = myMap.keySet(); c) Set<String> mapKeySet = myMap.getKeySet(); d) Set<String> mapKeySet = myMap.keySet();

d

75) Which data structure would best be used for storing a set of numbers and sorting them in ascending order? a) queue b) stack c) list d) array

d

76) Which of the following algorithms would be efficiently executed on an ArrayList? a) add 1 element to the middle of a list with n elements b) add n / 2 elements to a list with n / 2 elements 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

d

77) What operation is least efficient in a LinkedList? a) Adding an element in a position that has already been located. b) Linear traversal step. c) Removing an element when the element's position has already been located. d) Random access of an element.

d

82) You intend to use a hash set with your own object class. Which of the following statements is NOT correct? a) You do not have to do anything additional. You can use the hashCode function of the Object class. b) You can create your own function to compute a hashCode value. c) You can override the hashCode method in the Object class to provide your own hashCode method. d) Your class's hashCode method does not need to be compatible with its equals method.

d

88) Assume that you have declared a stack named myStack to hold String elements. Which of the following statements will correctly remove an element from myStack? a) myStack.remove(); b) myStack.get(); c) myStack.delete(); d) myStack.pop();

d

93) Which operations from the list data structure could be used to implement the push and pop operations of a stack data structure? I addLast II addFirst III removeFirst a) I b) II c) I and II d) II and III

d

97) Assume that you have declared a queue named myQueue to hold String elements. Which of the following statements will correctly insert an element into myQueue? a) myQueue.insert("apple"); b) myQueue.put("apple"); c) myQueue.push("apple"); d) myQueue.add("apple");

d

a) Once you have located the correct position, adding elements in the middle of a linked list is inefficient. b) Visiting the elements of a linked list in random order is efficient. c) When a node is removed, all nodes after the removed node must be moved down. d) Linked lists should be used when you know the correct position and need to insert and remove elements efficiently.

d

106) Suppose we create a deque (double-ended queue) data structure. It is basically a queue, with its addLast and removeFirst operations, but we also add the addFirst and removeLast operations. If a line at the grocery store resembles a deque more than a queue, what is the most likely reason? I the cashier is very fast II the line is very long III the cashier is very slow a) I b) II c) I and II d) II and III

d) II and III

5) A collection without an intrinsic order is called a ____. a) list b) stack c) set d) queue

c

89) Assume that you have declared a stack named myStack to hold String elements. Which of the following statements will correctly retrieve the top element from myStack without removing it? a) myStack.peek(); b) myStack.get(); c) myStack.next(); d) myStack.pop();

a

104) Consider the following code snippet: Queue<String> stringQueue = new LinkedList<String>(); stringQueue.add("ab"); stringQueue.add("abc"); stringQueue.add("a"); while (stringQueue.size() > 0) { System.out.print(stringQueue.remove() + ","); } What output will be produced when this code is executed? a) ab,abc,a, b) a,abc,ab, c) a,ab,abc, d) abc,ab,a,

a

13) We might choose to use a linked list over an array list when we will not require frequent ____. I random access II inserting new elements III removing of elements a) I b) II c) III d) II and III

a

95) Print jobs submitted to a printer would probably be stored in which type of data structure? a) queue b) linked list c) stack d) hash table

a

15) A binary search requires ____ access. a) sequential b) random c) sorted d) arbitrary

b

105) Suppose we create a deque (double-ended queue) data structure. It is basically a queue, with its addLast and removeFirst operations, but we also add the addFirst and removeLast operations. Which of the following is best modeled by the deque data structure? a) A toll booth on a highway. b) A cross country race. c) A computer keyboard typing buffer. d) A Memorial Day parade.

c

57) Complete the following code snippet, which is intended to determine if a specific value in a variable named targetWord appears in a set of String values named mySet: for (String aWord : mySet) { _______________________ { System.out.println ("The word " + targetWord + " was found."); } ) a) if (mySet.equalsIgnoreCase(targetWord)) b) if (mySet == targetWord) c) if (mySet.contains(targetWord)) d) if (mySet.get(targetWord))

c

64) Your program uses a Map structure to store a number of user ids and corresponding email addresses. Although each user must have a unique id, two or more users can share the same email address. Select an appropriate expression to complete the method below, which adds a new id and email address to the map only if the id is not already in use. If the id is already in use, an error message is printed. public static void addUserID(Map<String, String> users, String id, String email) { String currentEmail = users.get(id); if (___________________) { users.put(id, email); } else { System.out.println(id + " is already in use."); } } a) currentEmail.equals(email) b) !currentEmail.equals(email) c) currentEmail == null Maha Otaibi 113 d) currentEmail != null

c

55) Assume that you have declared a set named mySet to hold String elements. Which of the following statements will correctly insert an element into mySet? a) mySet.insert("apple"); b) mySet.put(apple"); c) mySet.push("apple"); d) mySet.add("apple");

d

6) A collection that allows items to be added only at one end and removed only at the other end is called a ____. a) list b) stack c) set d) queue

d

71) You need to access values in the order in which they were added (first in, first out), and not randomly. Which collection type should you use? a) Map b) Hashtable c) Stack d) Queue

d