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LeetCode Prep

The Curriculum

Every chapter, ordered from foundations to advanced. Prerequisites guide the path — master the basics and the harder patterns unlock.

Data Structures

1

Arrays & Hashing

The foundation: indexing, hash maps, and frequency counting.

Hashing & Frequency Maps

Use hash maps/sets for O(1) lookups, deduplication, and counting.

18 problems (3 quiz · 15 code)
Prefix Sums

Precompute running sums to answer range queries in O(1).

Prereqs: Hashing & Frequency Maps

7 problems (2 quiz · 5 code)
2

Strings

String manipulation, parsing, and encoding.

String Manipulation

Iterate, build, and transform strings efficiently.

16 problems (2 quiz · 14 code)
Anagrams & Encoding

Group, compare, and encode strings using canonical keys.

Prereqs: Hashing & Frequency Maps

7 problems (2 quiz · 5 code)
3

Stacks & Queues

LIFO/FIFO structures, monotonic stacks, and deques.

Stacks & Monotonic Stack

Use a stack for matching, parsing, and next-greater-element problems.

16 problems (2 quiz · 14 code)
Queues & Deques

Use FIFO queues and double-ended queues for windows and BFS.

Prereqs: Stacks & Monotonic Stack

5 problems (2 quiz · 3 code)
4

Linked Lists

Pointer manipulation, reversal, and cycle detection.

Traversal & Reversal

Walk, build, and reverse singly linked lists with pointers.

9 problems (2 quiz · 7 code)
Fast & Slow Pointers

Detect cycles and find midpoints with two-speed pointers.

Prereqs: Traversal & Reversal

7 problems (2 quiz · 5 code)
5

Trees & BSTs

Binary tree traversal, recursion on trees, and search trees.

Tree Traversals (DFS/BFS)

Traverse binary trees recursively and level-by-level.

Prereqs: Traversal & Reversal

17 problems (3 quiz · 14 code)
Binary Search Trees

Exploit BST ordering for search, insertion, and validation.

Prereqs: Tree Traversals (DFS/BFS)

6 problems (2 quiz · 4 code)
6

Heaps & Priority Queues

Top-K, streaming medians, and scheduling with heaps.

Heaps & Top-K

Use heaps for top-K, k-way merges, and streaming order statistics.

Prereqs: Tree Traversals (DFS/BFS)

14 problems (3 quiz · 11 code)
7

Tries

Prefix trees for fast string lookups and autocomplete.

Tries & Prefix Trees

Build prefix trees for fast word and prefix queries.

Prereqs: Tree Traversals (DFS/BFS), String Manipulation

6 problems (2 quiz · 4 code)
8

Graphs

Graph representation, traversal, and connectivity.

Graph Representation & Traversal

Model graphs as adjacency lists/matrices and traverse them.

Prereqs: Tree Traversals (DFS/BFS)

7 problems (2 quiz · 5 code)
Union-Find (Disjoint Set)

Track connectivity with union by rank and path compression.

Prereqs: Graph Representation & Traversal

5 problems (2 quiz · 3 code)

Algorithms

1

Two Pointers & Sliding Window

Linear-scan patterns for pairs, subarrays, and substrings.

Two Pointers

Converge pointers to solve pair, palindrome, and partition problems.

Prereqs: Hashing & Frequency Maps

16 problems (2 quiz · 14 code)
Sliding Window

Maintain a moving window to optimize subarray/substring scans.

Prereqs: Two Pointers

14 problems (3 quiz · 11 code)
2

Binary Search

Searching sorted data and binary searching the answer space.

Binary Search on Arrays

Halve the search space on sorted (and rotated) arrays.

Prereqs: Hashing & Frequency Maps

16 problems (2 quiz · 14 code)
Binary Search on the Answer

Binary search a monotonic feasibility function over a value range.

Prereqs: Binary Search on Arrays

6 problems (2 quiz · 4 code)
3

Recursion & Backtracking

Recursive enumeration of subsets, permutations, and combinations.

Recursion Fundamentals

Define base cases and recursive cases that shrink the problem.

7 problems (2 quiz · 5 code)
Backtracking

Explore choices with prune-and-undo over subsets and permutations.

Prereqs: Recursion Fundamentals

17 problems (3 quiz · 14 code)
4

Greedy

Locally optimal choices that yield a global optimum.

Greedy Algorithms

Prove and apply a greedy choice that stays globally optimal.

11 problems (2 quiz · 9 code)
5

Dynamic Programming

Overlapping subproblems, memoization, and tabulation.

1-D Dynamic Programming

Define a state and recurrence over a single dimension.

Prereqs: Recursion Fundamentals

19 problems (3 quiz · 16 code)
2-D Dynamic Programming

Grid and two-sequence DP (edit distance, LCS, unique paths).

Prereqs: 1-D Dynamic Programming

10 problems (2 quiz · 8 code)
Knapsack & Subset DP

Choose items under a capacity/target constraint.

Prereqs: 1-D Dynamic Programming

5 problems (2 quiz · 3 code)
6

Graph Algorithms

BFS/DFS patterns, topological sort, and shortest paths.

BFS & DFS Patterns

Flood fill, connected components, and shortest unweighted paths.

Prereqs: Graph Representation & Traversal

11 problems (2 quiz · 9 code)
Topological Sort

Order a DAG and detect cycles (course scheduling).

Prereqs: BFS & DFS Patterns

7 problems (2 quiz · 5 code)
Shortest Paths

Dijkstra for weighted graphs and BFS for unweighted ones.

Prereqs: BFS & DFS Patterns

7 problems (2 quiz · 5 code)
7

Intervals

Merging, scheduling, and sweeping over intervals.

Interval Merging & Scheduling

Sort and sweep intervals to merge, insert, and detect overlaps.

Prereqs: Greedy Algorithms

7 problems (2 quiz · 5 code)
8

Bit Manipulation & Math

Bitwise tricks, number theory, and math-heavy problems.

Bit Manipulation

Use XOR, masks, and shifts for O(1)-space tricks.

12 problems (2 quiz · 10 code)
Math & Number Theory

GCD, primes, modular arithmetic, and overflow-safe math.

11 problems (2 quiz · 9 code)

System Design

1

System Design Fundamentals

Scalability, latency vs throughput, load balancing, and caching.

Scalability & Performance

Reason about latency vs throughput and scale up vs scale out.

Load Balancing & Proxies

Distribute traffic with load balancers, reverse proxies, and health checks.

Prereqs: Scalability & Performance

Caching & CDNs

Add caches and CDNs with the right write/eviction policy.

Prereqs: Scalability & Performance

2

Data Storage & Scaling

Choosing data stores, sharding, replication, and indexing.

SQL vs NoSQL & Data Modeling

Match the data store and schema to access patterns.

Prereqs: Scalability & Performance

Partitioning & Replication

Shard for scale and replicate for availability and reads.

Prereqs: SQL vs NoSQL & Data Modeling

Indexing & Query Performance

Speed reads with the right indexes and understand their cost.

Prereqs: SQL vs NoSQL & Data Modeling

3

Distributed Systems

CAP & consistency, messaging, idempotency, and rate limiting.

CAP & Consistency Models

Trade consistency, availability, and partition tolerance.

Prereqs: Partitioning & Replication

Message Queues & Async Processing

Decouple services with queues, pub/sub, and streams.

Prereqs: Scalability & Performance

Resilience & Rate Limiting

Stay correct under failure with idempotency, retries, and rate limits.

Prereqs: Message Queues & Async Processing

4

Cloud System Design

Cloud building blocks, autoscaling, serverless, reliability, and cost.

Cloud Building Blocks

Compose compute, object storage, managed databases, and networking.

Prereqs: Scalability & Performance

Autoscaling & Multi-Region

Scale elastically and survive zone/region failure in the cloud.

Prereqs: Load Balancing & Proxies, Cloud Building Blocks

Serverless & Event-Driven Cloud

Build event-driven systems with functions, managed queues, and streams.

Prereqs: Cloud Building Blocks, Message Queues & Async Processing

Reliability, Observability & Cost

Operate cloud systems with SLOs, monitoring, and cost control.

Prereqs: Cloud Building Blocks

5

Design Case Studies

Driving an end-to-end design interview on real products.

End-to-End Design Cases

Drive a design interview from requirements to a scaled architecture.

Prereqs: Caching & CDNs, Partitioning & Replication, Cloud Building Blocks

AI & FDE

1

LLM Foundations

Tokens, context, prompting, embeddings, and model selection.

Prompting & Context

Design prompts, manage context windows, and choose decoding settings.

Embeddings & Similarity

Choose embedding models and similarity metrics for retrieval.

Prereqs: Prompting & Context

Model Selection

Trade quality, latency, cost, and privacy when picking models.

Prereqs: Prompting & Context

2

RAG & Retrieval

Chunking, vector search, hybrid retrieval, re-ranking, and citations.

RAG Pipeline Design

Ingest, chunk, index, retrieve, and generate with grounding.

Prereqs: Embeddings & Similarity

Retrieval Quality

Hybrid search, re-ranking, filters, and citation strategies.

Prereqs: RAG Pipeline Design

3

Agents & Tools

Tool calling, orchestration, memory, multi-agent, and failure modes.

Tool Calling

Define tools, schemas, and safe execution boundaries.

Prereqs: Prompting & Context

Agent Orchestration

Plan-act loops, memory, multi-agent, and failure handling.

Prereqs: Tool Calling

4

ML Systems

Training vs inference, feature stores, online/offline paths, and drift.

Feature Stores & Paths

Online/offline features, training-serving skew, and pipelines.

Inference Serving

Batching, quantization, GPUs, and serving architectures.

Prereqs: Model Selection

5

Production AI

Latency, cost, caching, guardrails, observability, and evals in prod.

Evals & Quality

Offline/online evals, golden sets, LLM-as-judge, and regression gates.

Prereqs: RAG Pipeline Design

Safety & Guardrails

Prompt injection, PII, content filters, and policy enforcement.

Prereqs: Tool Calling

Cost & Latency

Caching, routing, streaming, and token economics in production.

Prereqs: Inference Serving

6

FDE Delivery

Customer discovery, scoping, integration, rollout, and stakeholder delivery.

Discovery & Scoping

Frame customer problems, MoSCoW scope, and success metrics.

Integration & Deploy

Connectors, ACLs, on-prem/cloud deploy, and rollout plans.

Prereqs: Discovery & Scoping

Stakeholders & Delivery

Workshop facilitation, demos, change management, and support handoff.

Prereqs: Discovery & Scoping

7

AI & FDE Case Studies

End-to-end AI architect and forward-deployed interview cases.

AI & FDE Cases

Drive AI architect and FDE interviews from requirements to delivery.

Prereqs: RAG Pipeline Design, Evals & Quality, Discovery & Scoping

Agent Engineering

1

AI Developer Workstation

Cursor, Claude Code, Codex, Copilot — surfaces, modes, and the daily agent loop.

Agent Workstation

Choose the right agent surface and mode, and run a disciplined spec → execute → review loop.

2

Context Engineering

AGENTS.md, CLAUDE.md, rules, instructions, and token budgets.

Context Engineering

Write repo memory files and spend the context budget deliberately.

Prereqs: Agent Workstation

3

Superstar Practices

Spec-driven development, TDD with agents, parallel worktrees, model routing, debugging, and agents in CI.

Superstar Practices

Spec before prompting, test first, parallelize safely, route models, debug with evidence, and run agents in CI.

Prereqs: Context Engineering

4

Agent Skills

SKILL.md, progressive disclosure, triggering, evaluation, and trust.

Agent Skills

Design, trigger, evaluate, and vet SKILL.md skills across tools.

Prereqs: Context Engineering

5

Plugins & Subagents

Commands, subagents, plugins, marketplaces, and portability.

Plugins & Subagents

Pick between commands, skills, subagents, and plugins, and distribute them to a team.

Prereqs: Agent Skills

6

OpenClaw

Self-hosted agent gateway, channels, ClawHub, bundles, and safety.

OpenClaw

Run an always-on agent gateway safely and reuse skills and plugins from other ecosystems.

Prereqs: Agent Skills

7

Model Context Protocol

Primitives, transports, client config, context cost, and auth.

MCP

Configure, design, and secure Model Context Protocol servers.

Prereqs: Context Engineering

8

LangGraph & Workflows

Workflow vs agent, state, checkpoints, interrupts, and create_agent.

LangGraph & Workflows

Choose workflows vs agents and build durable, human-in-the-loop graphs.

Prereqs: MCP

9

Build Your Own Agents

Claude Agent SDK, OpenAI Agents SDK, Cursor SDK, browser/computer use, A2A, and operating agents.

Build Your Own Agents

Pick the right layer and build agents with coding-agent SDKs, general agent SDKs, browser tools, and A2A.

Prereqs: MCP, LangGraph & Workflows

10

Hooks, Security & Evals

Hooks, sandboxes, reviewing agent output, evals, and team rollout.

Hooks, Security & Evals

Enforce guardrails with hooks and sandboxes, review agent output, and evaluate agent setups.

Prereqs: Agent Skills, MCP