Question 1

How many times can an array with 4,096 elements be cut into two equal pieces?

Accepted Answer

A)  16 
B)  12 
C)  10 
D)  8 
A)  16 
B)  12 
C)  10 
D)  8

Question 2

Consider the sort method shown below for selection sort:
public static void sort(int[] a) {
For (int i = 0; i < a.length - 1; i++)
{
int minPos = minimumPosition(i);
swap(minPos, i);
}
}
Suppose we modify the loop condition to read i < a.length. What would be the result?

Accepted Answer

A)  An exception would occur. 
B)  The sort would work, but run one more iteration. 
C)  The sort would work but with one less iteration. 
D)  The sort would work exactly the same as before the code modification. 
A)  An exception would occur. 
B)  The sort would work, but run one more iteration. 
C)  The sort would work but with one less iteration. 
D)  The sort would work exactly the same as before the code modification.

Question 3

Suppose objects a and b are from a user-defined class that implements the Comparable interface. What must be true about the return value of a.compareTo(b) for the compareTo method that this class implements?

Accepted Answer

A)  It must return 1 if a comes before b, 0 if they are the same, and -1 if a comes after b. 
B)  It must return -1 if a comes before b, 0 if they are the same, and 1 if a comes after b. 
C)  It must return a positive value if a comes before b, 0 if they are the same, and a negative value if a comes after b. 
D)  It must return a negative value if a comes before b, 0 if they are the same, and a positive value if a comes after b. 
A)  It must return 1 if a comes before b, 0 if they are the same, and -1 if a comes after b. 
B)  It must return -1 if a comes before b, 0 if they are the same, and 1 if a comes after b. 
C)  It must return a positive value if a comes before b, 0 if they are the same, and a negative value if a comes after b. 
D)  It must return a negative value if a comes before b, 0 if they are the same, and a positive value if a comes after b.

Question 4

Which of the following arrays can be used in a call to the Arrays.sort method?
I Any array with primitive numeric data, such as int, double, …
II Arrays of String or numeric wrapper classes like, Integer, Double, …
III Any class that implements the Comparable interface

Accepted Answer

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

Question 5

Which sort algorithm starts with an initial sequence of size 1, which is assumed to be sorted, and increases the size of the sorted sequence in the array in each iteration?

Accepted Answer

A)  insertion sort 
B)  selection sort 
C)  merge sort 
D)  quicksort 
A)  insertion sort 
B)  selection sort 
C)  merge sort 
D)  quicksort

Question 6

In each iteration, selection sort places which element in the correct location?

Accepted Answer

A)  The smallest in the array. 
B)  The smallest element not yet placed in prior iterations. 
C)  The largest element in the array. 
D)  A random element. 
A)  The smallest in the array. 
B)  The smallest element not yet placed in prior iterations. 
C)  The largest element in the array. 
D)  A random element.

Question 7

Suppose we are using binary search on an array with approximately 1,000,000 elements. How many visits should we expect to make in the worst case?

Accepted Answer

A)  1 
B)  16 
C)  20 
D)  30 
A)  1 
B)  16 
C)  20 
D)  30

Question 8

Which notation, big-Oh, theta, or omega describes the growth rate of a function?
I big-Oh
II theta
III omega

Accepted Answer

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

Question 9

After one iteration of selection sort working on an array of 10 elements, what must hold true?

Accepted Answer

A)  The array cannot be sorted. 
B)  One element must be correctly placed. 
C)  At least two elements are correctly placed. 
D)  The largest element is correctly placed. 
A)  The array cannot be sorted. 
B)  One element must be correctly placed. 
C)  At least two elements are correctly placed. 
D)  The largest element is correctly placed.

Question 10

Suppose a developer gets class XYZ files and documentation from a subcontractor. This class does not implement the Comparable interface. What must be true in order for the developer to sort an array of XYZ objects without modifying the xyz class?

Accepted Answer

A) The XYZ class must implement the Sortable interface. B) XYZ objects must be randomly distributed. C) XYZ objects must be ordered. D) The developer must supply a comparator object belonging to a class that implements the Comparator interface. A) The XYZ class must implement the Sortable interface. B) XYZ objects must be randomly distributed. C) XYZ objects must be ordered. D) The developer must supply a comparator object belonging to a class that implements the Comparator interface.

Question 11

If you increase the size of a dataset fivefold, how much longer does it take to sort it with the selection sort algorithm?

Accepted Answer

A)  Approximately 5 times longer 
B)  Approximately 20 times longer 
C)  Approximately 25 times longer 
D)  Approximately 100 times longer 
A)  Approximately 5 times longer 
B)  Approximately 20 times longer 
C)  Approximately 25 times longer 
D)  Approximately 100 times longer

Question 12

Suppose an algorithm requires a total of 3n3 + 2n2 - 3n + 4 visits. In big-Oh notation, the total number of visits is of what order?

Accepted Answer

A)  n2 * n2 
B)  n2 
C)  n6 
D)  n3 
A)  n2 * n2 
B)  n2 
C)  n6 
D)  n3

Question 13

A version of which sort algorithm is used in the sort method in the Java Arrays class?

Accepted Answer

A)  merge sort 
B)  quicksort 
C)  selection sort 
D)  insertion sort 
A)  merge sort 
B)  quicksort 
C)  selection sort 
D)  insertion sort

Question 14

In the textbook, we found that the number of element visits for merge sort totaled
N + 5n log2 n. Which of the following is the appropriate big-Oh notation for merge sort?

Accepted Answer

A)  5n log2 n 
B)  n + log2 n 
C)  n + 5n 
D)  n log2 n 
A)  5n log2 n 
B)  n + log2 n 
C)  n + 5n 
D)  n log2 n

Question 15

If the Arrays static method binarySearch is called on an array of 10 elements and returns a value of 10, what can be concluded?
I the element is not found
II that value cannot be returned from method binarySearch
III if added, the element would be the largest element in the array

Accepted Answer

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

Question 16

The sort method of the Arrays class sorts arrays containing objects of classes that implement the ____ interface.

Accepted Answer

A)  Sortable 
B)  Ordered 
C)  Array 
D)  Comparable 
A)  Sortable 
B)  Ordered 
C)  Array 
D)  Comparable

Question 17

A portion of your program implements a loop in which each step contains a fixed number of actions. What can you conclude about the running time of this section of code?

Accepted Answer

A)  Its running time will be O(n). 
B)  Its running time will be O(n2). 
C)  Its running time will be O(log (n)). 
D)  Its running time will be O(n log (n)). 
A)  Its running time will be O(n). 
B)  Its running time will be O(n2). 
C)  Its running time will be O(log (n)). 
D)  Its running time will be O(n log (n)).

Question 18

The method findLargest examines the elements of an array arr which contains non-negative values
Public static int findLargest(int[] arr)
{
Int curLargest = -1;
For (int i = 0; i = curLargest)
{
CurLargest = arr[i];
}
}
Return curLargest;
}
What can you conclude about the running time of this section of code?

Accepted Answer

A)  Its running time will be O(n). 
B)  Its running time will be O(n2). 
C)  Its running time will be O(log (n)). 
D)  Its running time will be O(n log (n)). 
A)  Its running time will be O(n). 
B)  Its running time will be O(n2). 
C)  Its running time will be O(log (n)). 
D)  Its running time will be O(n log (n)).

Question 19

If a call to the Arrays static method binarySearch returns a value of 7, what can be concluded?
I the element is not in the array
II the element is at index 7
III the element occurs 7 times in the array

Accepted Answer

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

Exam 14: Sorting and Searching

How many times can an array with 4,096 elements be cut into two equal pieces?

Consider the sort method shown below for selection sort: public static void sort(int[] a) { For (int i = 0; i < a.length - 1; i++) { int minPos = minimumPosition(i); swap(minPos, i); } } Suppose we modify the loop condition to read i < a.length. What would be the result?

Suppose objects a and b are from a user-defined class that implements the Comparable interface. What must be true about the return value of a.compareTo(b) for the compareTo method that this class implements?

Which of the following arrays can be used in a call to the Arrays.sort method? I Any array with primitive numeric data, such as int, double, … II Arrays of String or numeric wrapper classes like, Integer, Double, … III Any class that implements the Comparable interface

Which sort algorithm starts with an initial sequence of size 1, which is assumed to be sorted, and increases the size of the sorted sequence in the array in each iteration?

In each iteration, selection sort places which element in the correct location?

Suppose we are using binary search on an array with approximately 1,000,000 elements. How many visits should we expect to make in the worst case?

Which notation, big-Oh, theta, or omega describes the growth rate of a function? I big-Oh II theta III omega

After one iteration of selection sort working on an array of 10 elements, what must hold true?

Suppose a developer gets class XYZ files and documentation from a subcontractor. This class does not implement the Comparable interface. What must be true in order for the developer to sort an array of XYZ objects without modifying the xyz class?

If you increase the size of a dataset fivefold, how much longer does it take to sort it with the selection sort algorithm?

Suppose an algorithm requires a total of 3n3 + 2n2 - 3n + 4 visits. In big-Oh notation, the total number of visits is of what order?

A version of which sort algorithm is used in the sort method in the Java Arrays class?

In the textbook, we found that the number of element visits for merge sort totaled N + 5n log2 n. Which of the following is the appropriate big-Oh notation for merge sort?

If the Arrays static method binarySearch is called on an array of 10 elements and returns a value of 10, what can be concluded? I the element is not found II that value cannot be returned from method binarySearch III if added, the element would be the largest element in the array

The sort method of the Arrays class sorts arrays containing objects of classes that implement the ____ interface.

A portion of your program implements a loop in which each step contains a fixed number of actions. What can you conclude about the running time of this section of code?

If a call to the Arrays static method binarySearch returns a value of 7, what can be concluded? I the element is not in the array II the element is at index 7 III the element occurs 7 times in the array

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Suppose an algorithm requires a total of 3n³ + 2n² - 3n + 4 visits. In big-Oh notation, the total number of visits is of what order?

In the textbook, we found that the number of element visits for merge sort totaled N + 5n log₂n. Which of the following is the appropriate big-Oh notation for merge sort?