Concepts

One idea per page.

Every idea behind the systems, classes and algorithms here, one page each, grouped into topics. Read a subject's board in order, follow its learning path, or open any page you need.

Your tracksHLDLLDDSA

HLD

High-Level Design (HLD)

not started

Fundamental concepts for designing scalable systems.

0 of 119 pages21 h of reading

Starts with Designing a System: 3 pages, about 27 min.

First page · Designing a SystemHow to approach a system designcore · 11 minStart

20 topics77 core42 deep dives

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LLD

Low-Level Design (LLD)

not started

Object-Oriented Design and Design Patterns.

0 of 73 pages10 h of reading

Starts with Approach: 6 pages, about 50 min.

First page · ApproachWhat low-level design iscore · 8 minStart

10 topics57 core16 deep dives

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DSA

Data Structures & Algorithms

not started

Data structures and algorithms, each one run step by step in pseudocode.

0 of 44 pages4 h of reading

Starts with Measuring: 1 page, about 7 min.

First page · MeasuringBig-O notation & analysiscore · 7 minStart

9 topics34 core10 deep dives

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One idea, one page

Each page explains one idea, with figures and code where they help, and most end with a few questions to check yourself.

Core first, deep dives later

Core pages are what everyone needs. Deep dives go further into one idea, and can wait until a problem asks for them.

Read once, counted everywhere

A page counts once you've read it, or when you mark that you already know it, here and on the learning paths alike.