Lesson 1 / 42

What is DSA?

A data structure organises data; an algorithm is a recipe that operates on it.

Two halves of one skill

A data structure decides how data is stored and connected (array, list, tree, graph). An algorithm is a finite sequence of steps that transforms input into a desired output. Good code picks the structure that makes the algorithm cheap.

Kitchen analogy

The data structure is how you arrange your pantry — labelled jars vs. one big box. The algorithm is the recipe. The same recipe is fast with a tidy pantry and slow when you dig through the box each time.

Why interviews test it

DSA questions reveal whether you can spot the underlying pattern, reason about cost, and handle edge cases — skills that transfer to real system work far more than trivia does.

How to use this course

For each topic: understand the picture first, then the operations, then the code. If you can redraw the diagram from memory, you understand it.