Deck 14: Recursion

Question 1

A problem can be solved recursively if it can be broken down into successive smaller problems that are identical to the overall problem.

Answer 1

True

Question 2

Recursion can be a powerful tool for solving repetitive problems and is an important topic in upper-level computer science courses.

Answer 2

True

Question 3

A method is called from the main method for the first time. It then calls itself seven times. What is the depth of recursion?

A) 1
B) 7
C) 8
D) 6

Answer 3

B

Question 4

When recursive methods directly call themselves, it is known as

A) direct recursion
B) indirect recursion
C) basic recursion
D) static recursion

Question 5

The recursive case does not require recursion so it stops the chain of recursive calls.

Question 6

__________ occurs when method A calls method B which in turn calls method
A)

A) Dynamic recursion
B) Linear recursion
C) Direct recursion
D) Indirect recusion

Question 7

The __________ is at least one case in which a problem can be solved without recursion.

A) recursive case
B) base case
C) termination point
D) pont of absolution

Question 8

Any problem that can be solved recursively can also be solved iteratively, with a loop.

Question 9

Like a loop, a recursive method must have which of the following?

A) a statement that increments the control variable
B) a control variable initialized to a starting value
C) some way to control the number of time it repeats
D) All of these

Question 10

Without a base case, a recursive method will call itself only once and stop.

Question 11

Which of the following problems can be solved recursively?

A) greatest common denominator
B) Towers of Hanoi
C) binary search
D) All of these.

Question 12

In the __________, we must always reduce the problem to a smaller version of the original problem.

A) partition case
B) base case
C) lessening case
D) recursive case

Question 13

A recursive method can have only one base case.

Question 14

In a recursive program, the number of times a method calls itself is known as

A) the call count
B) the cyclic identity
C) the method heap
D) the depth of recursion

Question 15

Whereas a recursive algorithm might result in faster execution time, the programmer might be able to design an iterative algorithm faster.

Question 16

A method that calls itself is a __________ method.

A) recursive
B) redundant
C) binary
D) derived

Question 17

Recursion is never absolutely required to solve a problem.

Question 18

The Towers of Hanoi is a mathematical game that is often used in computer science textbooks to illustrate the power of recursion.

Question 19

The recursive binary search algorithm is a good example of repeatedly breaking a problem down into smaller pieces until it is solved.

Question 20

The actions performed by the JVM that take place with each method call are sometimes referred to as

A) overhead
B) allocation
C) overflow
D) retention

Question 21

To use recursion for a binary search, what is required before the search can proceed?

A) The array must include only integers.
B) The array can only include numerical values.
C) The array must be sorted.
D) All of these are required.

Question 22

In the following code that uses recursion to find the greatest common divisor of a number, what is the base case?
public static int gcd(int x, int y)
{
If (x % y == 0)
Return y;
Else
Return gcd(y, x % y);
}

A) gcd(int x, int y)
B) if (x % y == 0)
Return y;
C) else
Return gcd(y, x % y);
D) Cannot tell from this code

Question 23

In the following code that uses recursion to find the factorial of a number, what is the base case?
private static int factorial(int n)
{
If (n == 0)
Return 1;
Else
Return n * factorial(n - 1);
}

A) factorial(int n)
B) if (n == 0)
Return 1;
C) else
Return n * factorial(n - 1);
D) Cannot tell from this code

Question 24

Given the following code that uses recursion to find the factorial of a number, how many times will the else clause be executed if n = 5?
private static int factorial(int n)
{
If (n == 0)
Return 1;
Else
Return n * factorial(n - 1);
}

A) 3
B) 4
C) 5
D) 6