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 computes the average of all the numbers in an array.

If we have $n$ numbers and each number is denoted by $a_i$ $(where \: i = 0, 1, 2, ..., n-1)$, the average is the $sum$ of the numbers divided by $n$. This is represented as follows:
$$
{\displaystyle average={\frac {1}{n}}\sum _{i=0}^{n-1}a_{i}={\frac {a_{0}+a_{1}+a_{2}+\cdots +a_{n-1}}{n}}} 
$$

> Try solving this problem recursively.

## Input
1. A `testVariable` containing an array of numbers.
2. The `currentIndex` of the array.

>  Note: The array, `testVariable`, can't be empty, i.e., it will always have at least one
element.

## Output
Average of all numbers in the input array.

## Sample Input
```python
testVariable = [10, 2, 3, 4, 8, 0] 
currentIndex = 0
```

## Sample Output
```
4.5
```

## Try it Yourself
Try this challenge yourself before examining the solution. Good luck!

Given an array of numbers, compute the average of those numbers recursively.

Recursion Fundamentals

Iteration Vs. Recursion

Recursion with Numbers

Recursion with Strings

Recursion with Arrays

Recursion with Data Structures

Conclusion

Challenge 1: Average of Numbers

Problem Statement