Everything you need to go from zero to confident in mathematics and data structures & algorithms. Built for self-learners who started late and want to catch up fast.
Follow this order. Each topic builds on the one before it. Don't skip ahead -- the foundations make everything else click.
Start from the very basics and work your way up to the maths every computer scientist needs. Every topic has explanations, worked examples, formulas, and quizzes.
Numbers, BODMAS, fractions, decimals, percentages, ratios, exponents, and negative numbers.
Start HereVariables, equations, functions, polynomials, quadratics, logarithms, and exponent rules.
EssentialArithmetic and geometric progressions, sum formulas, n(n+1)/2, and why nested loops are O(n²).
EssentialShapes, angles, area, volume, trigonometry, coordinate geometry, and transformations.
EssentialLimits, derivatives, integrals, and their applications in CS and machine learning.
IntermediateLogic, sets, proofs, counting, graph theory, Big-O notation, and recurrence relations.
CS CoreVectors, matrices, eigenvalues, transformations, and applications in ML and graphics.
CS CoreProbability rules, Bayes' theorem, distributions, statistics, and CS applications.
CS CoreBinary, hex, octal, bitwise operations (AND, OR, XOR), bit manipulation, how files and data are stored as bytes, and C++ bitwise programming.
EssentialMaster every data structure and algorithm you need for LeetCode and technical interviews, with code in Python and JavaScript.
Everything explained from zero: what data structures are, time complexity with the math, every core structure, algorithms, and a problem-solving framework.
Start Here650 curated LeetCode problems organized by topic. Complete this list and you'll be ready for any interview.
EssentialArray operations, two pointers, sliding window, prefix sum, and string manipulation.
Start HereLIFO and FIFO structures, implementations, deques, and monotonic stack patterns.
FundamentalHash map internals, frequency counting, Two Sum, Group Anagrams, and building from scratch.
FundamentalSingly and doubly linked lists, fast/slow pointers, reversal, and cycle detection.
CoreBinary search trees, all traversals, DFS, BFS, and balanced tree concepts.
CoreBFS, DFS, Dijkstra's, topological sort, union-find, and cycle detection.
IntermediateAll sorting algorithms, binary search variants, and built-in sorting pitfalls.
CoreTwo pointers, sliding window, backtracking, prefix sum, greedy, and the pattern cheat sheet.
Key ResourceTop-down vs bottom-up, 1D and 2D DP, knapsack, LCS, and the 5-step framework.
AdvancedHeaps, tries, union-find, segment trees, bit manipulation, and math for interviews.
AdvancedLearn a systems-level programming language in depth and understand how operating systems actually work.
Data types, pointers (single through triple indirection), RAII, smart pointers, vectors, strings, STL containers, and modern C++ features.
EssentialGo fundamentals, structs, interfaces, goroutines & channels, building HTTP backends, CLIs, testing, concurrency patterns, and Go for DSA.
EssentialV8 engine, execution context, closures, prototypes, the event loop, Proxy/Reflect, ES6+ features, modules, and memory management.
EssentialGenerics, conditional types, mapped types, utility types, infer, keyof, decorators, declare module, namespaces, and tsconfig deep dive.
EssentialV8 + libuv architecture, event loop phases, streams, buffers, child_process, worker threads, cluster, and the module system.
EssentialProcesses, syscalls, scheduling, threads, locks, virtual memory, paging, file systems, and security. Companion to the free OSTEP textbook.
EssentialWhat Linux is, Unix vs Linux, the kernel and shell, directory structure, apt package management, Bash scripting, .bashrc, ANSI terminal codes, and more.
EssentialGit internals, branches as pointers, the DAG, rebase, interactive rebase, cherry-pick, squash, reset vs revert, reflog, GitHub CLI, GitLab CLI, and advanced workflows.
EssentialOSI model, TCP/IP, DNS, HTTP/HTTPS, TLS handshakes, WebSockets, REST vs GraphQL vs gRPC, ports, and network debugging tools.
EssentialAWS/GCP/Azure, compute & storage, serverless, CI/CD, Terraform, load balancers, CDNs, managed databases, and avoiding bill shock.
IntermediateContainers from scratch -- images, Dockerfiles, volumes, networking, Docker Compose, multi-container apps, and production best practices.
EssentialContainer orchestration -- Pods, Deployments, Services, scaling, self-healing, YAML configs, kubectl, and when to use K8s vs Docker Compose.
IntermediateMessage queues, Pub/Sub patterns, topics, fan-out, RabbitMQ, Apache Kafka, AWS SQS/SNS, consumer groups, and event-driven architecture.
IntermediateSet up a VPS from scratch, SSH keys, firewalls, reverse proxies, SSL, Docker deployments, Coolify, and self-hosted tools -- all on a $4/month server.
EssentialThe JavaScript and TypeScript ecosystem explained: tooling, testing, and building real projects.
npm/yarn/pnpm, package.json, Webpack, Vite, esbuild, Babel, SWC, module resolution, linting, monorepos, and npm audit.
EssentialVitest, Jest, mocking, spies, async testing, HTTP API testing, snapshots, coverage, TDD, and Playwright for E2E.
EssentialBuild CLIs, TUIs with Ink, HTTP APIs (Express/Fastify/Hono), an AI git commit tool, SDKs, npm publishing, and Docker for TS.
IntermediateThe best free resources to supplement your learning. Use these alongside this site.
Full-length university lectures on Pre-Algebra through Calculus III. The best maths teacher on YouTube -- explains everything from fundamentals with patience and clarity.
Highly RecommendedFree video lessons and practice for every maths topic from arithmetic to linear algebra. Perfect for filling gaps.
Beautiful visual explanations of linear algebra, calculus, and more. Watch Essence of Linear Algebra and Essence of Calculus.
Curated LeetCode roadmap with video explanations for every problem. The best free DSA resource.
Practice coding problems sorted by topic, difficulty, and company.
Animated visualizations of data structures and algorithms. See exactly how they work step by step.
Understanding how you think changes how you learn. If your brain demands axioms over vibes, this is for you.