Free DSA Course — Data Structures & Algorithms for Placements
Learn Data Structures & Algorithms free — arrays, hashing, linked lists, stacks, queues, recursion, sorting, searching, trees, heaps, graphs and dynamic programming, with Python examples and practice. The #1 skill for coding interviews.
TL;DR: Learn Data Structures & Algorithms free — arrays, hashing, linked lists, stacks, queues, recursion, sorting, searching, trees, heaps, graphs and dynam…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Free Dsa course: 12 lessons, from the basics through to the advanced topics interviewers actually ask about. Every lesson is free, needs no sign-up, and runs in your browser with an editor and instant AI feedback.
Dsa Course Syllabus — 12 Lessons
Work through them in order, or jump to the topic you need. 12 lessons include worked explanations and runnable examples.
Foundations
- What is DSA & Big-O Complexity — A data structure is a way of organising data so it can be used efficiently (an array, a linked list, a tree).
Linear Structures
- Arrays & Two Pointers — An array stores elements in contiguous memory, so accessing any index is O(1).
- Hash Maps & Sets — A hash map (Python dict) stores key → value pairs and gives average O(1) insert, delete and lookup by using a hash function to jump straight to where a key is stored.
- Linked Lists — A linked list stores each element in a node that also holds a pointer to the next node.
- Stacks & Queues — A stack is Last-In-First-Out (LIFO) — like a stack of plates.
Algorithms
- Recursion & Backtracking — Recursion is when a function calls itself on a smaller version of the problem.
- Searching & Binary Search — Linear search scans every element until it finds the target — O(n).
- Sorting Algorithms — Sorting arranges data in order and unlocks binary search, deduplication and many greedy algorithms.
- Dynamic Programming — Dynamic Programming (DP) solves problems that have overlapping subproblems and optimal substructure — the answer is built from answers to smaller versions of the same problem, and those smaller answers repeat.
Non-Linear Structures
- Trees & Binary Search Trees — A tree is a hierarchical structure of nodes with one root; each node has children.
- Heaps & Priority Queues — A heap is a special binary tree that keeps the smallest (min-heap) or largest (max-heap) element at the root.
- Graphs — BFS & DFS — A graph is a set of nodes (vertices) connected by edges.
Who this Dsa course is for
School and college students in India starting from zero, and anyone revising Dsa for placements, board practicals or a project. There is no prerequisite beyond being able to type — the first lessons assume no programming background at all.
How to study this course
- Read the lesson, then run the example in the built-in editor before moving on — reading code is not the same as writing it.
- Try the practice task at the end of each lesson. Getting it wrong and fixing it is where the learning happens.
- When you are stuck, ask the free AI Tutor to explain that specific line rather than skipping ahead.
🤖 Stuck on any of these? Ask Syllab's free AI Tutor to explain step by step →