The ultimate guide to recursion interviews in JavaScript. Developed by FAANG engineers. Practice with real-world interview questions and get interview-ready in just a few hours.

If you’ve ever struggled with solving problems using recursion, or if you have to brush up your skills for an interview, this course is for you.

We'll start with the basics of what recursion is and why it’s important before diving into practicing solving actual questions. 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 to solve complex real-world problems. We hope that through practicing recursion, you will be able to ace all recursion related questions in interviews at top tech companies.

Recursion for Coding Interviews in JavaScript

# 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 examining 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?