The ultimate guide to recursion interviews. Developed by FAANG engineers, practice with real-world C++ problems, interactive code playgrounds, and get interview-ready in just a few hours.

If you’ve ever struggled with solving coding problems using recursion, or if you’ve just got an interview coming up and want to brush up on your knowledge, you’ll definitely find this course helpful.
 
You’ll start with the basics of what recursion is and why it’s important before diving into what it looks like in practice. You’ll see how recursion can help you solve a variety of different math, string, and data structure problems, using interactive code playgrounds you can execute directly in your browser. You’ll have access to detailed explanations and visualizations for each problem to help you along the way.  
 
By the time you’re done, you’ll be able to use what you’ve learned to solve complex real-world problems, and even advance more easily through your interviews at top tech companies.

Recursion for Coding Interviews in C++

# What is iteration? 

**Iterative code** is a block of code that runs in a **loop**. In other words, the same code is repeated over and over again. The idea seems much similar to that of recursion. So where does the difference lie? 



# Is there a difference? 

Within recursion and iteration, there are multiple differences. These differences give these two implementations of repeated code their own uses. 

* The first difference to note is that recursion is always called on a **function**. Therefore, it is called a process. On the other hand, iterative code is applied on **variables** and is a set of **instructions** that are called upon repeatedly. 

* Recursive code will **terminate** on a base case condition whereas iterative code will either run for a **particular number of loops** or until a specified **condition** is met. 

* An **infinite** recursion can lead to the system crashing whereas with iterative code, it will just consume more CPU cycles.

* Recursive code has an **overhead** time for each recursive call it makes, unlike iterative code.

* Recursive code is **smaller and neater** in length than iterative code. 

* Recursive code is **slower** than iterative code as it not only runs the program but also has to invoke stack memory. 

* Recursion uses the **stack** to store the variable changes for each recursive call, whereas iterative code does not. 

This lesson will teach you the differences between recursion and iteration.

Recursion Fundamentals

Recursion with Numbers

Recursion With Strings

Recursion With Arrays

Recursion with Data Structures

Recursion vs. Iteration