Design and Analysis of Algorithms Chapter 3: Recursion

FeasibleSteelDrums avatar
FeasibleSteelDrums
·
·
Download

Start Quiz

Study Flashcards

16 Questions

What is the definition of a recursive function?

A function that calls itself, either directly or indirectly.

What is the purpose of the base case in a recursive function?

To simplify the problem until reaching the base case.

What is the recursion step in a recursive function?

The function calls itself to work on the smaller problem.

What is the outcome when a recursive function reaches the base case?

The function returns a result to the main function.

What is the algebraic relationship used to define the factorial function recursively?

𝑛! = 𝑛 × (𝑛 - 1)!

What is the recursive definition of the factorial function?

𝑓𝑎𝑐𝑡(𝑛) = 𝑛 × 𝑓𝑎𝑐𝑡(𝑛 - 1)

What is the process of finding the factorial of a number using a recursive function?

Calling the function with a smaller input until reaching the base case.

What happens when a recursive function terminates?

The function returns a result to the main function.

What is the main advantage of using recursion in problem-solving?

It provides a natural way to solve problems with a recursive structure

What happens when a recursive function reaches the base case?

The function returns a result and terminates

What is the role of the base case in a recursive function?

To provide a trivial solution to the problem

Why is recursion useful for solving the Towers of Hanoi puzzle?

Because it allows for a divide-and-conquer approach

What is the outcome of the recursive calls in a recursive function?

A sequence of progressively smaller problems

What is the purpose of the recursive call in a recursive function?

To divide the problem into smaller subproblems

What is the result of the factorial function when n is 1?

1

What is the relationship between the recursive function and the problem it solves?

The function is a recursive structure that mirrors the problem

Study Notes

Recursion

  • Recursion is a phenomenon where a function invokes itself, either directly or indirectly, to solve a problem.
  • A recursive function knows how to solve only the simplest case(s), also known as base case(s).
  • In a recursive function, the function calls a copy of itself to work on a smaller problem, referred to as a recursive call or the recursion step.

Characteristics of Recursion

  • The recursion step leads to multiple recursive calls, dividing the problem into smaller subproblems.
  • Recursion terminates when each call simplifies the problem until reaching the base case, forming a sequence of progressively smaller problems.
  • Upon reaching the base case, the function returns a result, propagating back up the call stack until the final result is returned to the main function.

Example: Recursive Factorial

  • A recursive definition of the factorial function is based on the algebraic relationship: 𝑛!= 𝑛 · (𝑛 – 1)!
  • The recursive function 𝑓𝑎𝑐𝑡(𝑛) is defined as: 𝑓𝑎𝑐𝑡(𝑛) = 𝑛 × 𝑓𝑎𝑐𝑡(𝑛 − 1), and 𝑓𝑎𝑐𝑡(1) = 1.
  • To find the factorial of a number, the function calls itself with a smaller input until it reaches the base case, where the result is returned and propagated back up the call stack.

Recursion

  • Recursion is a phenomenon where a function invokes itself, either directly or indirectly, to solve a problem.
  • A recursive function knows how to solve only the simplest case(s), also known as base case(s).
  • In a recursive function, the function calls a copy of itself to work on a smaller problem, referred to as a recursive call or the recursion step.

Characteristics of Recursion

  • The recursion step leads to multiple recursive calls, dividing the problem into smaller subproblems.
  • Recursion terminates when each call simplifies the problem until reaching the base case, forming a sequence of progressively smaller problems.
  • Upon reaching the base case, the function returns a result, propagating back up the call stack until the final result is returned to the main function.

Example: Recursive Factorial

  • A recursive definition of the factorial function is based on the algebraic relationship: 𝑛!= 𝑛 · (𝑛 – 1)!
  • The recursive function 𝑓𝑎𝑐𝑡(𝑛) is defined as: 𝑓𝑎𝑐𝑡(𝑛) = 𝑛 × 𝑓𝑎𝑐𝑡(𝑛 − 1), and 𝑓𝑎𝑐𝑡(1) = 1.
  • To find the factorial of a number, the function calls itself with a smaller input until it reaches the base case, where the result is returned and propagated back up the call stack.

This quiz covers the basics of recursion, including its importance, examples, and methods of solving recursion equations. It also includes the Towers of Hanoi puzzle and the rabbit problem.

Make Your Own Quizzes and Flashcards

Convert your notes into interactive study material.

Get started for free
Use Quizgecko on...
Browser
Browser