by javinpaul

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.

Earlier, I shared some free books to learn data structures and algorithms, and in this article, you will learn about some of the best data structure and algorithm courses that are available for free online.

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.

Course #1: 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.

Course #2: 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.

In this part, you will learn essential data structures like linked lists, stacks, queues, binary trees, and hash tables, and searching and sorting algorithms like binary search, quicksort, mergesort, insertion sort etc.

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.

Course #3: 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.

Talking about the social proof, both Algorithms Part 1 and Algorithms Part 2 are highly recommended courses and have impressive reviews and ratings.

Course #4. Data Structures in Java

This is an introductory online course on data structures, algorithms, and complexity analyses. It will teach you design, implementation, and analyses of basic data structures using the Java language.

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.

Course #5. Easy to Advanced Data Structures

Update: this course is no longer free, but it's a great course and may be worth it for you. This data structure and algorithm courses from Udemy is for all those people who want to learn data structures from an absolute basic to advanced level.

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.

Easy to Advanced 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.

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.

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