The ultimate recursion guide! Master basics, solve real-world problems, and get interview-ready in hours with FAANG engineers’ proven strategies.

If you’ve ever struggled with solving coding problems using recursion, or if you need to brush up your recursion skills for an interview, this course is for you! We will start with the basics of recursion before we practice solving actual coding problems. You’ll have access to detailed explanations and visualizations for each problem to help you along the way.

By the time you have completed this course, you’ll be able to use all the concepts of recursion to solve complex, real-world problems. We hope that this course will help you ace all the recursion related questions during interviews at top tech companies!

Recursion for Coding Interviews in Python

# Problem Statement
Implement a function that takes two numbers, `testVariable1` and `testVariable2` and returns their **greatest common divisor**.

## What is the Greatest Common Divisor?
The Greatest Common Divisor of two or more integers is the largest positive integer that divides each of the integers. 

For example, take two numbers $42$ and $56$.

$42$ can be completely divided by $1$, $2$, $3$, $6$, $7$, $14$, $21$ and $42$.

$56$ can be completely divided by $1$, $2$, $4$, $7$, $8$, $14$, $28$ and $56$.

Therefore the **greatest common divisor** of $42$ and $56$ is $14$.

## Input
Two variables `testVariable1` and `testVariable2` containing numbers.

## Output
The greatest common divisor of `testVariable1` and `testVariable2`.

## Sample Input
```
6, 9
```
## Sample Output
```
3
```
## Try it Yourself
Try this challenge yourself before moving on to the solution. Good luck!

Given two numbers, find their greatest common divisor.

Recursion Fundamentals

Iteration Vs. Recursion

Recursion with Numbers

Recursion with Strings

Recursion with Arrays

Recursion with Data Structures

Conclusion

Challenge 1: Find the Greatest Common Divisor

Problem Statement

What is the Greatest Common Divisor?