The ultimate guide to recursion interviews! Gain a structured approach to recursion basics and solve real-world problems. Get interview-ready in just a few hours with strategies developed by FAANG engineers.

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
Imagine you have been given the task to schedule some tasks. The tasks are represented as **vertices** of the graph, and if a task $u$ must be completed before a task $v$ can be started, then there is an edge from $u$ to $v$ in the graph.

Find the order of the **tasks** so that each task can be performed in the right order.

This problem can be solved if we find the **topological sorting** of the graph.

### What is Topological Sort of a Graph?
A topological sort gives the order in which to perform the tasks. 

Topological sorting for **Directed Acyclic Graph (DAG)** is a linear ordering of vertices. For every directed edge $\{u,v\}$ vertex $u$ comes before $v$ in the ordering. 

> Topological sorting for a graph is not possible if the graph is not a **DAG**.

The algorithm for topological sorting can be visualized as follows:

# Problem Statement
Imagine you have been given the task to schedule some tasks. The tasks are represented as **vertices** of the graph, and if a task $u$ must be completed before a task $v$ can be started, then there is an edge from $u$ to $v$ in the graph.

Find the order of the **tasks** so that each task can be performed in the right order.

This problem can be solved if we find the **topological sorting** of the graph.

## What is Topological Sort of a Graph?
A topological sort gives the order in which to perform the tasks. 

Topological sorting for **Directed Acyclic Graph (DAG)** is a linear ordering of vertices. For every directed edge $\{u,v\}$ vertex $u$ comes before $v$ in the ordering. 

> Topological sorting for a graph is not possible if the graph is not a **DAG**.

The algorithm for topological sorting can be visualized as follows:

Given a graph, return a list containing nodes the of the graph in topological order.

Recursion Fundamentals

Iteration Vs. Recursion

Recursion with Numbers

Recursion with Strings

Recursion with Arrays

Recursion with Data Structures

Conclusion

Challenge 3: Topological Sorting of a Graph

Problem Statement

What is Topological Sort of a Graph?