Data Structures & Algorithms Notes

Practice50 MCQs & 23 exam questions with answers & mark schemes →

A complete, self-contained Data Structures & Algorithms course — free, and open to anyone, anywhere. 8 lessons published so far — each with notes, worked examples, a diagram you can move, flashcards and a quiz — and more are being written.

Also called Free online course, Self-study course.

01

Data Structures

▸Data StructuresArrays, lists, stacks, queues, trees · 24 min · 6 questions→

02

Algorithms and Complexity

▸Algorithms & Big-OSorting, searching, and measuring cost honestly · 22 min · 6 questions→

03

Recursion

▸RecursionA routine that calls itself, and the stack that makes it possible · 22 min · 8 questions→

04

Trees, Heaps & Priority Queues

▸Trees, Heaps & Priority QueuesHierarchies that keep search fast — and the queue that always serves the most urgent first · 24 min · 6 questions→

05

Hashing & Hash Tables

▸Hashing & Hash TablesTurning a key straight into an address, for near-instant lookup · 22 min · 6 questions→

06

Graphs & Graph Algorithms

▸Graphs & Graph AlgorithmsModelling anything that connects to anything — and the algorithms that walk it · 26 min · 6 questions→

07

Dynamic Programming

▸Dynamic ProgrammingSolve each subproblem once, remember it, and an impossible problem becomes easy · 24 min · 6 questions→

08

Object-Oriented Design

▸Object-Oriented ProgrammingFour ideas that organise large programs · 18 min · 6 questions→

Frequently asked questions

What does Data Structures & Algorithms cover?

All 8 chapters — Data Structures, Algorithms and Complexity, Recursion, and more. The finished lessons carry notes, worked examples, an interactive diagram and a quiz; the remaining topics are mapped and being written.

Are there practice questions or past-paper-style questions?

Yes — 50 multiple-choice questions and 23 exam-style questions with mark schemes, all with answers, on the Data Structures & Algorithms practice page.

Are the Data Structures & Algorithms notes free?

Yes — completely free, with no sign-up or login. Every topic has notes, worked examples, an interactive diagram you can change, flashcards and a quiz that explains each answer.