Question 1

If a call to the Arrays static method binarySearch returns a value of -10, what can be concluded?
I the element is not in the array
II the element is at index 10
III the element can be inserted at index 9

Accepted Answer

A binarySearch returning -10 indicates the element is not in the array (I) and suggests it can be inserted at index 9 (III) to maintain sorted order.

Question 2

The ____ class contains a sort method that can sort array lists.

Accepted Answer

The Collections class in Java provides a sort method that can be used to sort elements in an ArrayList.

Question 3

Which of the following classes implement the Comparable interface?
I Date
II Collections
III String

Accepted Answer

Both Date and String classes implement the Comparable interface, allowing them to be compared to other instances of the same type. Collections is a utility class and does not implement Comparable.

Question 4

The code segment below prints some of the elements in an array with size n. Select an expression to complete the code segment so that the resulting algorithm has O(log n) running time. for __________________________
{
System.out.println(array[j]);
}

Accepted Answer

The expression (int j = 1; j < array.length; j = j * 2) results in a loop that runs logarithmically with respect to the size of the array, as j is multiplied by 2 in each iteration.

Question 5

If you want to use the Comparable interface, you must implement a single method called ____.

Accepted Answer

The Comparable interface requires the implementation of the compareTo method to define the natural ordering of objects.

Question 6

The code segment below displays a pattern of asterisks. Select an expression to complete the code segment so that the resulting algorithm has O(n) running time. for (int k = 0; k < n; k++)
{
For _______________________
{
System.out.print("*");
}
System.out.println();
}

Accepted Answer

The answer of The code segment below displays a pattern...

Question 7

Given the following code snippet for searching an array:
Int[] arr = {3, 8, 12, 14, 17};
Int newVal = 15;
Int pos = Arrays.binarySearch(arr, newVal);
What value will pos have when this code is executed?

Accepted Answer

Arrays.binarySearch() returns a negative value if the element is not found. The negative value is the (-(insertion point) - 1). In this case, the insertion point would be 5, so pos will be -5.

Question 8

An algorithm that tests whether the first array element is equal to any of the other array elements would be an ____ algorithm.

Accepted Answer

The answer of An algorithm that tests whether the first...

Question 9

The method checkArray examines an array arr: public static boolean checkArray(int[] arr)
{
If (arr[0] >= arr[arr.length -1])
{
Return true;
}
Return false;
}
What can you conclude about the running time of this section of code?

Accepted Answer

The method only checks the first and last elements of the array, which takes constant time, regardless of the array's size.

Question 10

A portion of your program includes the loops shown in the code snippet below to examine the elements of two arrays, arr1 and arr2, both of length n:
Int matches = 0;
For (int i = 0; i < arr1.length; i++)
{
For (int j = 0; j < arr2.length; j++)
{
If (arr1[i].equals(arr2[j]))
{
Matches++;
}
}
}
What can you conclude about the running time of this section of code?

Accepted Answer

The code snippet contains two nested loops, each of which iterates over an array of length n. Therefore, the running time of this section of code will be O(n²).

Question 11

Assume that names is an array of String objects that has been initialized with a large number of elements. Select the statement that would sort the elements in names in ascending alphabetic order.

Accepted Answer

The Arrays.sort(names) method sorts the entire array in ascending order.

Question 12

Assume that bands is an ArrayList of String objects which contains a number of elements in ascending order. Select a statement to complete the code segment below, which invokes the Java library binarySearch method to search for the string "Beatles". If the list does not already contain the string, it should be inserted in an appropriate location so that the list remains sorted.
Int index = Collections.binarySearch(bands, "Beatles");
If (index < 0)
{
__________________________
}

Accepted Answer

The binarySearch method returns (-(insertion point) - 1) if the element is not found. To find the correct insertion point, you need to use -1 - index.

Question 13

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

The answer of If the Arrays static method binarySearch is...

Question 14

A portion of your program includes the method shown in the code snippet below to examine the elements of an array arr: private int findElement(int[] arr, int newVal)
{
Int pos = Arrays.binarySearch(arr, newVal);
Return pos;
}
What can you conclude about the running time of this section of code?

Accepted Answer

The running time of the binary search algorithm used in Arrays.binarySearch is O(log(n)), as it divides the search interval in half each time.

Question 15

An algorithm that cuts the work in half in each step is an ____ algorithm.

Accepted Answer

An algorithm that cuts the work in half at each step typically has a logarithmic time complexity, represented as O(log(n)).

Question 16

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

The binarySearch method returns the index of the element if it is found in the array, or a negative value if it is not found. In this case, the method returned a value of 7, which means that the element is at index 7 in the array.

Question 17

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

Accepted Answer

The sort method of the Arrays class sorts arrays containing objects of classes that implement the Comparable interface, which defines the compareTo method for ordering objects.

Question 18

Given the following code snippet for searching an array:
Int[] arr = {23, 25, 29, 34, 42};
Int newVal = 15;
Int pos = Arrays.binarySearch(arr, newVal);
What value will pos have when this code is executed?

Accepted Answer

The binarySearch method returns a negative value if the element is not found. In this case, the element is not found, so pos will be -1.

Question 19

The binarySearch method of the Collections class returns a value in the form of -k - 1 when the target item you are searching for was not found in the array. What does k represent?

Accepted Answer

k represents the index of the first element that is greater than the target item, indicating where the target item would be inserted to maintain sorted order.

Question 20

The code segment below displays a table of numbers. Select an expression to complete the code segment, so that the resulting algorithm has O(n²) running time. for (int k = 1; k <= n; k++) { For _______________________ { System.out.print(j + " "); } System.out.println(); }

Accepted Answer

The correct answer is C because the inner loop iterates from 0 to k-1, which results in O(n^2) running time.

Quiz 14: Sorting and Searching

If a call to the Arrays static method binarySearch returns a value of -10, what can be concluded? I the element is not in the array II the element is at index 10 III the element can be inserted at index 9

The ____ class contains a sort method that can sort array lists.

Which of the following classes implement the Comparable interface? I Date II Collections III String

The code segment below prints some of the elements in an array with size n. Select an expression to complete the code segment so that the resulting algorithm has O(log n) running time. for __________________________ { System.out.println(array[j]) ; }

If you want to use the Comparable interface, you must implement a single method called ____.

The code segment below displays a pattern of asterisks. Select an expression to complete the code segment so that the resulting algorithm has O(n) running time. for (int k = 0; k < n; k++) { For _______________________ { System.out.print("*") ; } System.out.println() ; }

Given the following code snippet for searching an array: Int[] arr = {3, 8, 12, 14, 17}; Int newVal = 15; Int pos = Arrays.binarySearch(arr, newVal) ; What value will pos have when this code is executed?

An algorithm that tests whether the first array element is equal to any of the other array elements would be an ____ algorithm.

The method checkArray examines an array arr: public static boolean checkArray(int[] arr) { If (arr[0] >= arr[arr.length -1]) { Return true; } Return false; } What can you conclude about the running time of this section of code?

Assume that names is an array of String objects that has been initialized with a large number of elements. Select the statement that would sort the elements in names in ascending alphabetic order.

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

A portion of your program includes the method shown in the code snippet below to examine the elements of an array arr: private int findElement(int[] arr, int newVal) { Int pos = Arrays.binarySearch(arr, newVal) ; Return pos; } What can you conclude about the running time of this section of code?

An algorithm that cuts the work in half in each step is an ____ algorithm.

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

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

Given the following code snippet for searching an array: Int[] arr = {23, 25, 29, 34, 42}; Int newVal = 15; Int pos = Arrays.binarySearch(arr, newVal) ; What value will pos have when this code is executed?

The binarySearch method of the Collections class returns a value in the form of -k - 1 when the target item you are searching for was not found in the array. What does k represent?

The code segment below displays a table of numbers. Select an expression to complete the code segment, so that the resulting algorithm has O(n²) running time. for (int k = 1; k <= n; k++) { For _______________________ { System.out.print(j + " ") ; } System.out.println() ; }

Quiz 14: Sorting and Searching

If a call to the Arrays static method binarySearch returns a value of -10, what can be concluded? I the element is not in the array II the element is at index 10 III the element can be inserted at index 9

The ____ class contains a sort method that can sort array lists.

Which of the following classes implement the Comparable interface? I Date II Collections III String

The code segment below prints some of the elements in an array with size n. Select an expression to complete the code segment so that the resulting algorithm has O(log n) running time. for __________________________ { System.out.println(array[j]) ; }

If you want to use the Comparable interface, you must implement a single method called ____.

The code segment below displays a pattern of asterisks. Select an expression to complete the code segment so that the resulting algorithm has O(n) running time. for (int k = 0; k < n; k++) { For _______________________ { System.out.print("*") ; } System.out.println() ; }

Given the following code snippet for searching an array: Int[] arr = {3, 8, 12, 14, 17}; Int newVal = 15; Int pos = Arrays.binarySearch(arr, newVal) ; What value will pos have when this code is executed?

An algorithm that tests whether the first array element is equal to any of the other array elements would be an ____ algorithm.

The method checkArray examines an array arr: public static boolean checkArray(int[] arr) { If (arr[0] >= arr[arr.length -1]) { Return true; } Return false; } What can you conclude about the running time of this section of code?

Assume that names is an array of String objects that has been initialized with a large number of elements. Select the statement that would sort the elements in names in ascending alphabetic order.

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

A portion of your program includes the method shown in the code snippet below to examine the elements of an array arr: private int findElement(int[] arr, int newVal) { Int pos = Arrays.binarySearch(arr, newVal) ; Return pos; } What can you conclude about the running time of this section of code?

An algorithm that cuts the work in half in each step is an ____ algorithm.

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

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

Given the following code snippet for searching an array: Int[] arr = {23, 25, 29, 34, 42}; Int newVal = 15; Int pos = Arrays.binarySearch(arr, newVal) ; What value will pos have when this code is executed?

The binarySearch method of the Collections class returns a value in the form of -k - 1 when the target item you are searching for was not found in the array. What does k represent?

The code segment below displays a table of numbers. Select an expression to complete the code segment, so that the resulting algorithm has O(n2) running time. for (int k = 1; k <= n; k++) { For _______________________ { System.out.print(j + " ") ; } System.out.println() ; }

The code segment below displays a table of numbers. Select an expression to complete the code segment, so that the resulting algorithm has O(n²) running time. for (int k = 1; k <= n; k++) { For _______________________ { System.out.print(j + " ") ; } System.out.println() ; }