DSA + System Design Mind-Map

A markdown-first knowledge base for pattern recognition, fast recall, and teaching — purpose-built for MAANG / big-MNC SDE3+ interviews.

Coding solutions in Go (primary) and JavaScript (alt). System design covers Fundamentals → Building Blocks → HLD → LLD → Deep Dives.

How to use this repo

This is a mind map, not a tutorial. Read it like an index:

You see a problem in an interview.
Skim the Patterns overview and match the recognition cues — that tells you the pattern.
Open the matching pattern file → it lists representative problems and a generic recipe.
Open the problem file → 11-section template: brute → optimal → walkthrough → similar problems.
Use the Similar problems map to jump sideways across problems with the same recipe.

For system design:

Read the System design curriculum for the learning order.
Use the System design interview framework (RESHADED) when given any new design question.

Top-level layout

Section	What it holds
Patterns	~20 pattern mind-maps (the recognition layer)
Topics	226 unique problem mind-maps (see the Problem index; `152` canonical under `dp-1d`)
Cheatsheets	Complexity, Go/JS idioms, DS ops, recognition decision tree
System design fundamentals	CAP, consistency, scalability, back-of-envelope, etc.
Building blocks	LB, cache, MQ, sharding, consensus, rate limiter, ID generation, etc.
HLD case studies	~20 full HLD case studies
LLD exercises	~15 OOD / machine-coding designs
Design patterns	GoF + concurrency patterns (Go + JS)
Deep dives	Kafka, Redis, DynamoDB, Postgres, Cassandra internals
Interview prep	Company playbooks, 12-week plan, behavioral STAR
Problem index	Master curated problem list (~250)
12-week roadmap	Phased 12-week study plan
Problem mind-map template	Strict template every problem file follows
Similar problems map	Cross-link map: problem → siblings (auto-index of all problem files)
`scripts/validate-problems.sh`	CI-friendly check: all 12 `##` sections under `topics/*/problems/.md`
`scripts/refresh-knowledgebase.sh`	After adds/edits: validate → regenerate the similar-problems map → refresh the AI knowledge base snapshot + `AGENTS.md` snapshot (repo root)
`.cursor/skills/knowledgebase-refresh/`	Cursor skill in repo root describing when and how to run the refresh workflow

Conventions

Diagrams: Every problem mind-map includes ## Diagram with a ```mermaid block (placed early, before approaches) for quick visual recall — see the Problem mind-map template. Pattern cards under Patterns follow the same rule (see the Pattern author template).
Naming: topics/<topic>/problems/NNN-kebab-name.md where NNN is the LeetCode number.
Templates are the source of truth for shape — see the Problem mind-map template, System design interview framework (RESHADED).
Mind-Map Tags at the bottom of each file (e.g. #hashmap #pair-sum) — use rg "#hashmap" to retrieve.
Code snippets: idiomatic Go first, JS second. Both must be runnable when copied into a main / REPL.

Continuation (agents & context)

AGENTS.md (repository root) — handoff checklist, validation command, canonical paths, auto inventory snapshot
AI knowledge base snapshot — machine-friendly repo inventory (updated by scripts/refresh-knowledgebase.sh)
Archived implementation plan — archived Cursor plan + completion snapshot
.cursor/rules/dsa-mind-map-repo.mdc — repo-specific Cursor rules (always applied in this workspace)
.cursor/skills/knowledgebase-refresh/SKILL.md — when to rescan the repo and refresh AI knowledge + AGENTS.md after changes
Further improvements backlog — optional upgrades (CI, static site, Anki export, CONTRIBUTING, etc.)
AI tooling roadmap — phased plan for implementing with AI: guardrails, automation, skills, static site, optional solutions/

Quick start

New to the repo? → 12-week roadmap
Forgot a pattern? → Pattern recognition cheatsheet
Picking a system-design Q to practice? → System design curriculum
Going to interview at company X? → Company interview playbooks

~250 curated problems chosen to cover ~90% of MAANG / big-MNC SDE3+ DSA rounds. Source blend: NeetCode 150 (base) + Grind 169 deltas + Striver SDE picks + Sean Prashad pattern fills + ~40 SDE3-tier Hards.