Free course · Technology
DSA From Zero to Job-Ready
A Practical Guide with Java
A free, 28-article course that takes you from basic problem solving to independently approaching common interview problems in Java. It explains each idea first, shows it in code you can run, and ends with exercises, solutions, an interview workflow and a study plan.
- 28
- lessons
- 5
- modules
- 9 h
- of reading
Curriculum
5 modules · 28 lessons · about 9 h
Module 1Foundations (Think Like a Programmer)4 lessons · 1 h 12 min
Module 2Data Structures and Recursion8 lessons · 2 h 43 min
- 05Arrays and Array-Based Problem Solving20 min
- 06Strings: Characters, Immutability, and Efficient Manipulation17 min
- 07Linked Lists: Nodes, Pointers, and Pointer Reasoning20 min
- 08Stacks and Queues19 min
- 09Hashing: HashMap, HashSet, and Frequency Patterns20 min
- 10Recursion and Backtracking24 min
- 11Trees and Binary Search Trees22 min
- 12Heaps and Priority Queues21 min
Module 3Core Algorithms and Reusable Patterns6 lessons · 1 h 59 min
- 13Searching and Sorting: Choose the Right Approach22 min
- 14Two Pointers: Solve Problems by Coordinating Indices18 min
- 15Sliding Window: Efficient Subarray and Substring Problems18 min
- 16Prefix Sums and Difference Arrays19 min
- 17Greedy Algorithms and Interval Problems22 min
- 18Bit Manipulation and Mathematical Patterns20 min
Module 4Advanced Interview Topics6 lessons · 2 h 10 min
Module 5From Practice to Job-Ready4 lessons · 1 h 24 min
This is a free course on data structures and algorithms (DSA), written for people who are starting from the beginning and want to become comfortable with the problems that coding interviews and online assessments ask. It uses Java for every implementation, but each idea is explained in plain language first, so the thinking carries over to any language.
Who it is for
- Students preparing for their first software-development job.
- Fresh graduates and early-career developers.
- Beginners who need DSA from the foundations, including preparation for campus placements and fresher interviews in India.
How the course is organised
Start with the first article and go in order, because each one builds on the ones before it.
Module | Articles | What it builds |
|---|---|---|
1. Foundations | How to approach problems, the Java you need, and how to measure speed | |
2. Data Structures and Recursion | Arrays, Strings, Linked Lists, Stacks and Queues, Hashing, Recursion and Backtracking, Trees and BSTs, Heaps | The essential structures, with recursion placed before trees |
3. Core Algorithms and Patterns | Searching and Sorting, Two Pointers, Sliding Window, Prefix Sums, Greedy and Intervals, Bits and Maths | Reusable techniques for many problems |
4. Advanced Interview Topics | Graphs, Shortest Paths and Topological Sort, DP Foundations, DP Practice, Tries, Range Queries and DSU | The harder topics, with essential and optional parts labelled |
5. From Practice to Job-Ready | Interview Workflow, Practice Project, 12-Week Plan, Placement Preparation | Turning knowledge into interview performance |
About the Java code
- The code targets Java 17 and uses classic syntax, so it is easy to follow.
- Complete programs start with a comment such as
// File: Main.javathat tells you what to name the file. Compile withjavac Main.javaand run withjava Main. - The text under each complete program shows the output the program printed when the course was written. If your output differs, trace the difference. That is a good way to learn.
- Fragments without that comment are illustrations, not complete programs.
How to study
Read once for the idea, trace the dry run by hand, type the code yourself, break it on purpose, and attempt every exercise before opening its solution. Revise after a day, a week and a month. The 12-week plan turns this into a schedule, and the first article explains the routine in detail.
Must-know and nice-to-know
Not every topic carries equal weight. As a rough guide for fresher roles, arrays, strings, hashing, sorting and searching, linked lists, stacks and queues, recursion, basic trees, two pointers and sliding window come first. Graphs, heaps, dynamic programming basics, greedy and prefix sums come next. Tries, segment trees and Fenwick trees are optional depth. Articles label optional material when they reach it.