Free Ways to Learn and Practise DSA, Compared Honestly

By Pooja Goenka · Published 2026-10-02 · Updated 2026-10-26

"Learn DSA" covers two separate jobs: understanding why a sliding window works, and solving forty unseen problems under a timer. Most people use one tool for both, and then wonder why they can follow every solution and still freeze on a blank editor.

I run LogicWiz, which has a free DSA course, so I have a stake in this. Everything below comes from each product's own page, read in early October 2026. Where a page did not say, I say that. Pricing and limits change, so check before you commit.

The two jobs

Understanding means seeing what the algorithm does to the data, step by step, and animations, diagrams and good explanations help with that.

Practice is retrieval under pressure. You need problems you have not seen, a judge that tells you if you are right, and enough volume that patterns stick. A tool can be excellent at one job and poor at the other, which is a good reason to use two.

VisuAlgo: the best free visualiser I know of

VisuAlgo comes from Associate Professor Steven Halim at the National University of Singapore, and its page says it is offered at no cost. It has 24 visualisation modules, including arrays, sorting, linked lists, heaps, hash tables, binary search trees, graphs, recursion and shortest paths, and it goes on to network flow and NP-hard problems. There is an online quiz system with randomly generated questions and automatic grading. Basic access needs no account, and accounts exist for progress tracking. The page says the mobile version supports only a subset of features and recommends a screen of at least 1366 by 768.

It will show you exactly how Dijkstra relaxes edges, but it will not ask you to solve a problem you have never seen, so it does little for interview practice. I would point anyone who finds pseudocode opaque until they watch it run here first.

USFCA visualisations: the classic, minimal tool

David Galles's visualisations at the University of San Francisco cover basic structures, recursion, search trees, hash tables, tries and B-trees, many sorting algorithms, graph algorithms and dynamic programming. The page offers a source-code option. It does not say what practice there is, and the page I read mentions neither a price nor an account.

It is handy for a quick look at one structure, with no sign-up and nothing else in the way.

LeetCode: the problem set everyone is measured against

LeetCode is the default problem set for many people preparing for coding interviews, and the volume of problems and the discussion around them are hard to match. The Premium page I read lists what the paid plan adds: company-specific interview questions, premium content and solutions, an interactive debugger, autocompletion, interview simulations, faster judging at peak hours, and an AI helper called Ask Leet. For India it listed ₹999 a month, or a yearly plan at ₹6,999.

The page does not list the free tier's contents, so I will not guess at them. What you can read from it is that the company-specific questions and the simulations are paid. For beginners, the catch is that LeetCode is built for people who already know the patterns, and it does far more testing than explaining. If you know the basics and need volume and realism, it is the obvious choice.

NeetCode: a roadmap that tells you what to do next

NeetCode's homepage describes interview roadmaps, organised study plans (Blind 75, NeetCode 150 and NeetCode 250), and more than 1,000 practice problems and video explanations. The roadmap breaks topics into an order, from arrays and hashing through two pointers, sliding window, trees and graphs to dynamic programming. It also lists courses, including a 25-hour Algorithms and Data Structures for Beginners. There is a Start Free option and a Pro plan; the homepage does not spell out what Pro adds, so check the pricing page.

What it does well is the order. Many people stall because they do not know what to study after arrays, and a roadmap answers that, which makes NeetCode a good fit for self-taught learners who want a path and explanations in video.

LogicWiz: visual lessons and practice in one place

The LogicWiz DSA course is free, with a growing library of curated problems, visual simulations for each concept, an AI helper for doubts, an in-browser code editor with automatic judging, and progress tracking with a daily streak. The concept pages cover arrays, hashing, two pointers, sliding window, linked lists, stacks and queues, trees, and searching and sorting, and there are foundation lessons on recursion, binary search, graphs and dynamic programming. I wrote about why visual explanations tend to beat video for this kind of learning, and the DSA course is built on that argument. There is no payment and no time limit. You can read the explanations without an account; writing and judging your own code needs a free one.

The 100-plus problems are chosen to teach each pattern, so it works well as the place you learn them. Once a pattern makes sense, a large problem set such as LeetCode or the NeetCode 150 and 250 lists is a good place to get repetitions in.

It suits beginners who want to see a concept before they are asked to solve problems on it, and who like to practise in the same place.

Side by side

How I would combine them

If you are new, start with the concept before the problem. Watch the algorithm run in VisuAlgo or a LogicWiz simulation until you can predict the next step without looking, then solve problems on it. If you are already comfortable, follow a roadmap such as NeetCode's for order and use LeetCode for volume and for simulating an interview.

Whatever you pick, keep a short log of the problems you got wrong and the pattern you missed. Redoing those a week later is worth more than a fresh problem.

Common questions

What is the best free way to learn DSA?

It depends on the job. For understanding, VisuAlgo's free animations are excellent. For a path and video explanations, NeetCode has a free option. For visual lessons with practice in the same place, LogicWiz is free. For problem volume, LeetCode.

Is LeetCode free?

LeetCode has a Premium plan that adds company-specific questions, premium solutions, a debugger and interview simulations, and in India it was listed at ₹999 a month when I checked. Check its Problems page for what the free tier includes.

Can I learn DSA without paying anything?

Yes. VisuAlgo and LogicWiz are free, NeetCode has a free option, and LeetCode has a free tier. What it costs you is time and discipline.

How many problems do I need to solve?

I don't think there is a right number. NeetCode's lists run to 150 and 250 problems and ours is a growing, curated library. What matters more is that you can explain why a solution works and spot the pattern in a problem you have not seen.

Do visualisations really help?

For understanding what an algorithm does to its data, they help a lot. They do not replace solving problems, because retrieval under pressure is a separate skill.