Data structures and algorithms are some of the most essential topics for programmers, both to get a job and to do well on a job. Good knowledge of data structures and algorithms is the foundation of writing good code.

If you are familiar with essential data structures e.g.

array,

string,

linked list, tree, map, and advanced data structures like tries, and self-balanced trees like AVL trees, etc., you'll know when to use which data structure and compute the CPU and memory cost of your code.

Even though you don't need to write your own array, linked list, or hashtable, given every major programming SDK provides them, e.g. JDK or C++ STL library, you will need to understand them so that you can use them in the right place.

Using the right data structure can drastically improve the performance of an algorithm.

Ideally, we should all learn

data structures and

algorithms in our schools and colleges, but it's rarely ever covered. Most of the programmers, including myself, only get introduced to a data structure in our computer science courses, but we didn't really learn the real-world importance of them, and that's why we didn't understand them better.

For us, they are just the algorithms and data structures e.g. some concept, not a tool that you can use to write good programs. We didn't know that Facebook would use them to store our details or that Google would use them to store web pages and link to search queries.

Anyway, it's never too late.

If you think that your data structure knowledge is not up to par or you want to improve your data structure knowledge, then you have come to the right place.

Free Courses to Learn Data Structures and Algorithms

Here is my list of some of the best courses to learn data structures and algorithms, which are also free. Many programmers think that free resources are not good, which is not true.

Even though they sometimes don't match the quality and coverage of paid resources, they are, in fact, the best resources to start with.

You can use these courses to familiarize yourself with the essential data structures and learn some basics.

Some of them are particularly good from an interview point of view so you can use them alongside any book you are using to prepare for your

programming job interview.

1. Easy to Advanced Data Structures

This

course doesn't expect you to have any prior knowledge of data structures, but a basic prior knowledge of

Java is helpful.

The author @William Fiset is a Software Engineer at

Google and a former

ACM-ICPC world finalist and has excellent computer programming and problem-solving skills.

Talking about social proof, the

course has more than 25K students and an average 4.1 ratings from 683 rating which is impressive.

In short, it's a complete guide to learning everything there is to know about data structures.

This is also an ideal course for computer science students and working software professionals who want to learn data structures and algorithms from an interview perspective.

So, if you are looking to get a job with product-based companies like

Amazon,

Google,

Microsoft, or Facebook, you can use this course to kick-start your preparation.

2. Data Structure Concepts in C

This is another free, online algorithm and data structure training course, which aims to teach basic data structures in computer programming.

The data structures taught in the course include

Stack,

Queue, and

Linked List using the C programming language.

The primary goal of this

course is to make students and software engineers visualize how different data structures work.

This is not an exhaustive course, but you will learn about Stack, Queue, and

Linked List.

In short, it is a great course for programmers new to data structures and those who have just learned a programming language and want to learn the basics of how data structures work.

3. Algorithms Part 1 - Coursera

This is the

first part of a two-part series of courses covering algorithms and data structures on Courera by Robert Sedgewick.

You will also learn about core data structures and algorithms used in everyday applications and understand the trade-offs involved with choosing each data structure along with

traversal, retrieval, and update algorithms.

All the features of this course are available for free but it does not offer a certificate upon completion.

4) Algorithms - Part 2

This is the

second part of a two-part series of free online Coursera courses covering data structures and algorithms by Robert Sedgewick and Kevin Wayne, both are professors of Computer Science.

Robert Sedgewick is also the author of

Algorithms 4th Edition book, one of the most popular books on Algorithms for Java developers.

In

this part, you will learn about the graph- and string-processing algorithms.

You will also learn some advanced data structures and algorithms used in application development.

5. Data Structure in Java

The best part of

this course is the number of practical examples and that it focuses on intuition rather than formulas and mathematical proofs.

The

course provides a good introduction for "complexity analysis," which makes it possible to spot a poorly (and a great) performing program, even without the need for executing it.

That's all about some of the free data structure and algorithm courses available online. You can use these courses to learn data structures and algorithms at your own pace.

They may not all be comprehensive, but they do provide a good introduction. Once you go through these courses, you can pick a good book like Introduction to Algorithms to further supplement your knowledge.

Further Learning

Closing Notes

Thanks. You made it to the end of the article. Good luck with your programming Journey! It's certainly not going to be easy, but by following these courses, you are one step closer to mastering data structure and algorithms than others.