Question 1

Complete the following code snippet, which is intended to determine if a value is even or odd using mutual recursion:

Accepted Answer

The answer of Complete the following code snippet, which is...

Question 2

Which statement(s) about recursion are true?
i.Recursion is faster than iteration.
II.Recursion is often easier to understand than iteration.
III.Recursive design has an economy of thought.

Accepted Answer

Recursion is not generally faster than iteration due to the overhead of multiple function calls. However, it can be easier to understand and implement for certain problems, embodying an "economy of thought" by breaking down a problem into simpler, self-similar problems.

Question 3

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.Which line contains the recursive call in the permutations method?

Accepted Answer

The recursive call in the permutations method is on line #6 which calls the permutations method with a substring of the original word. This allows the method to find all possible permutations of the remaining letters in the word, which are then combined with the initial letter to form permutations of the original word.

Question 4

Recursion will take place if any of the following happen:
i.method A calls method B, which calls method C
II.method A calls method B, which calls method A
III.method A calls method A

Accepted Answer

Recursion occurs when a method calls itself. Option II describes a scenario where recursion occurs. Option III also describes recursion as method A calls itself, but this is not a common occurrence and often leads to infinite loops. Option I, on the other hand, describes method chaining, where one method calls another and so forth, but not necessarily leading to recursion. Therefore, the correct answer is B.

Question 5

In recursion, the recursive call is analogous to a loop ____.

Accepted Answer

In both recursion and loops, there is repetition of a certain set of actions until a certain condition is met. In loops, this is achieved through iteration or looping through the same set of actions multiple times until the condition for termination is met. Similarly, in recursion, a function repeatedly calls itself with a different input until a certain termination condition is met. Therefore, the analogous term for a loop in recursion is iteration.

Question 6

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.  If line #8 is changed to add the removed character to the end of each permutation of the shorter word, which change best describes the returned list?
result.add(s + word.charAt(i)); // line #8 revised

Accepted Answer

The answer of Consider the permutations method from the textbook,...

Question 7

Recursion does NOT take place if any of the following happen:
i.method A calls method B, which calls method C, which calls method B
II.method A calls method B, which calls method A
III.method A calls method B, B returns, and A calls B again

Accepted Answer

Recursion involves a method calling itself, either directly or indirectly. In option III, method A calling method B, B returning, and then A calling B again does not involve any method calling itself; it's a simple method call sequence. Options I and II involve indirect recursion, where methods call each other in a cycle, which is a form of recursion.

Question 8

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.How does the permutations method simplify its input for the recursive call?

Accepted Answer

The answer of Consider the permutations method from the textbook,...

Question 9

In a _____________, a set of cooperating methods calls each other repeatedly.

Accepted Answer

In mutual recursion, two or more methods call each other repeatedly. This can lead to infinite recursion if not implemented properly, but when implemented correctly, it can be a useful tool for solving certain problems. Option A refers to a situation where recursion never stops, and Option D is an error that occurs when the call stack exceeds its limit due to too many recursive function calls. Option B refers to a way of arranging objects, and is not related to the question.

Question 10

Which statement is true about backtracking?

Accepted Answer

Backtracking starts with a partial solution and explores all possible paths to get closer to the goal. It may abandon a partial solution if it reaches a dead-end but it always keeps track of previous choices to try alternative paths. It does not start from the end of the program or explore only one path.

Question 11

Consider the mutually recursive methods below.Select the method call that could be used to generate the output sequence: A5 B4 A3 B2 A1

Accepted Answer

The output begins with A5, indicating that the methodA(5) call was made first. The pattern continues with alternating calls to methodB with decreasing values and calls to methodA with decreasing values.

Question 12

In recursion, the non-recursive case is analogous to a loop ____.

Accepted Answer

The non-recursive case in recursion, often called the base case, is analogous to the termination condition in a loop, which determines when the loop should stop executing.

Question 13

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.Which line contains the terminating condition in the permutations recursive method?

Accepted Answer

The answer of Consider the permutations method from the textbook,...

Question 14

A termination condition in a loop is analogous to _____________ in a recursive method.

Accepted Answer

The answer of A termination condition in a loop is...

Question 15

Which of the following executions represent mutual recursion?
i.method E calls method T, which calls method F
II.method E calls method T, which calls method F, which calls method E
III.method F calls method F

Accepted Answer

Mutual recursion occurs when two or more functions call each other, creating a loop of calls. In option II, method E calls method T, which calls method F, which in turn calls method E, forming a mutual recursion. Options I and III do not represent mutual recursion; I is a simple chain of calls without looping back, and III is an example of direct recursion, not mutual recursion.

Question 16

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.What special cases for the simplest values are used by the permutations method to terminate the recursion?

Accepted Answer

The answer of Consider the permutations method from the textbook,...

Question 17

Which of the following statements about recursion is correct?

Accepted Answer

Recursion can often provide a more intuitive and concise solution to certain problems, particularly those that involve repetitive or self-similar tasks. However, it is important to ensure that there is a base case or terminating condition in the recursion to prevent it from infinitely looping. Additionally, whether a recursive or iterative solution is faster depends on the specific problem and implementation. Finally, simplifying the argument in each recursive call can help improve the efficiency of the solution.

Question 18

Which problem-solving technique examines partial solutions, abandons unsuitable ones, and returns to consider other candidate solutions.

Accepted Answer

Backtracking is a problem-solving technique where a partial or incomplete solution is examined, and if it is found to be unsuitable, it is abandoned, and the algorithm backtracks to consider other candidate solutions. This process continues until a suitable solution is found or all possible solutions have been evaluated. Recursion, traceback, and debugging are related but distinct techniques that are not specifically focused on exploring multiple candidate solutions in the same way as backtracking.

Question 19

Consider the following code snippet:  For any given value of n, what is the maximum number of function calls that could occur, including the original call?

Accepted Answer

The given code snippet is just a random string of characters, without any function names or code blocks. Therefore, it is not possible for any function calls to occur. The only function call that could occur is the original call to execute the code itself. Hence, the maximum number of function calls possible is 1. The correct answer is (D) 2, which is an incorrect option. Therefore, the answer is (D) only.

Quiz 13: Recursion

Complete the following code snippet, which is intended to determine if a value is even or odd using mutual recursion:

Which statement(s) about recursion are true? i.Recursion is faster than iteration. II.Recursion is often easier to understand than iteration. III.Recursive design has an economy of thought.

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.Which line contains the recursive call in the permutations method?

Recursion will take place if any of the following happen: i.method A calls method B, which calls method C II.method A calls method B, which calls method A III.method A calls method A

In recursion, the recursive call is analogous to a loop ____.

Recursion does NOT take place if any of the following happen: i.method A calls method B, which calls method C, which calls method B II.method A calls method B, which calls method A III.method A calls method B, B returns, and A calls B again

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.How does the permutations method simplify its input for the recursive call?

In a _____________, a set of cooperating methods calls each other repeatedly.

Which statement is true about backtracking?

Consider the mutually recursive methods below.Select the method call that could be used to generate the output sequence: A5 B4 A3 B2 A1

In recursion, the non-recursive case is analogous to a loop ____.

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.Which line contains the terminating condition in the permutations recursive method?

A termination condition in a loop is analogous to _____________ in a recursive method.

Which of the following executions represent mutual recursion? i.method E calls method T, which calls method F II.method E calls method T, which calls method F, which calls method E III.method F calls method F

Consider the permutations method from the textbook, which is intended to return all permutations of the word passed in as a parameter.What special cases for the simplest values are used by the permutations method to terminate the recursion?

Which of the following statements about recursion is correct?

Which problem-solving technique examines partial solutions, abandons unsuitable ones, and returns to consider other candidate solutions.

Consider the following code snippet: For any given value of n, what is the maximum number of function calls that could occur, including the original call?