Recursion

Question 1

What is recursion?

Answer 1

A programming technique where a function calls itself to solve a problem by breaking it into smaller versions of the same problem. Like solving a puzzle by solving smaller parts of the same puzzle.

Question 2

What is a base condition in recursion?

Answer 2

Factorial Example

The stopping condition that prevents infinite recursion. It’s the simplest case that can be solved directly without further recursive calls.
Example: In factorial(n), base case is when n=0 or n=1.

def factorial(n):
# Base case
if n == 0 or n == 1:
return 1
return n * factorial(n-1) #recursive case

Question 3

When is it appropriate to use recursion?

Answer 3

Use recursion when:

• Problem can be broken into smaller versions of itself
• Solution involves tree-like or nested structures
• Problems involve backtracking

Examples:
* Tree traversal
* Fibonacci sequence
* Directory traversal
* Divide and conquer algorithms