# HiSpeedAlgo (https://hispeedalgo.com)

> Deliberate practice, active recall, and AI interview coaching for software engineers. Master algorithmic patterns with zero noise. Published by HiWebEnterprise (https://hiwebenterprise.com).

## Overview & Mission
HiSpeedAlgo is an interactive algorithm mastery and technical interview preparation platform designed specifically for senior and staff software engineers preparing for rigorous coding screens at top technology companies (FAANG/MAMAA).

Rather than grinding hundreds of disconnected LeetCode problems, HiSpeedAlgo organizes curriculum into 12 core algorithmic mental models and 147 archetypes taught through a 4-stage deliberate practice methodology.

## 4-Stage Deliberate Practice Methodology
1. **Stage 1: Compare & Learn the Pattern** - Multi-language Rosetta Stone contrasting abstract template invariants with concrete FAANG implementations across Python, C#, Java, TypeScript, C++, Go, and Rust.
2. **Stage 2: Practice from Memory** - Active recall canvas where candidates reconstruct algorithmic templates from memory with real-time invariant verification before viewing answers.
3. **Stage 3: Senior SWE AI Mock Coach** - Simulated Senior/Staff SWE interview evaluating Big-O space/time tradeoffs, edge cases, invariant proofs, and code reviews in Monaco Editor.
4. **Stage 4: Solve on Your Own** - Automated in-browser execution sandbox testing implementations against rigorous verification test suites in Python, C#, Java, and TypeScript.

## 12 Core Algorithmic Patterns & 147 Archetypes
- **1. Two Pointers**: Opposite ends, sorted pair sums, palindrome verification, trapping rain water, 3Sum, container with most water.
- **2. Sliding Window**: Contiguous subarrays, monotonic window invariants, variable vs fixed size, longest substrings.
- **3. Binary Search**: Monotonic predicate partitioning (`feasible(x)`), boundary search, rotated sorted arrays, square roots, capacity allocation.
- **4. Fast & Slow Pointers**: Floyd's cycle detection, linked list middle, circular array cycles, happy number.
- **5. Linked List Reversal**: In-place pointer manipulation, sublist reversal, k-group reversal, palindrome linked list.
- **6. Tree Breadth-First Search (BFS)**: Level-order traversals, shortest path in unweighted graphs, zig-zag traversals, rotting oranges, word ladders.
- **7. Tree Depth-First Search (DFS)**: Path sums, lowest common ancestor, tree diameter, subtree serialization, flood fill.
- **8. Two Heaps & Priority Queues**: Running medians, top-k elements, interval scheduling, IPO, k-way merges.
- **9. Backtracking & Combinatorial Search**: Subsets, permutations, combinations, constraint satisfaction, pruning, N-Queens, Sudoku solver.
- **10. Dynamic Programming**: Memoization vs tabulation, 0/1 knapsack, unbounded knapsack, coin change, edit distance, longest common subsequence.
- **11. Graphs & Advanced Graph Algorithms**: Topological sort, cycle detection, Dijkstra's algorithm, bipartite graph validation.
- **12. Advanced Data Structures**: Trie (prefix tree), Union-Find (Disjoint Set Union), LRU Cache, LFU Cache, Monotonic Stacks.

## Supported Programming Languages
- Python 3 (`.py`)
- C# (.NET 8/9) (`.cs`)
- Java 21 (`.java`)
- TypeScript (`.ts`)
- C++ 20 (`.cpp`)
- Go 1.22 (`.go`)
- Rust (`.rs`)

## Pricing & Subscription Model
- **Core Curriculum**: 100% Free. All 12 patterns, 147 archetypes, and multi-language Rosetta Stone implementations are accessible without payment or credit card.
- **Compute Coins**: 40 free coins provided upon registration, +20 daily login bonus, and +25 referral bonus.
- **24-Hour AI Coaching Pass**: 5 compute coins grants unlimited AI interview coaching and code reviews for a continuous 24-hour period.
- **BYOK (Bring Your Own Key)**: Completely free unlimited AI coaching if the user provides their personal Google Gemini or OpenAI API key.
- **Zero Subscriptions**: HiSpeedAlgo does NOT charge recurring monthly or annual subscriptions. There are zero auto-renewals or unexpected billing cycles.

## Refund & Commercial Policies
Because the platform core curriculum is completely free and compute coins are earned through normal platform engagement (signup bonus, daily logins, referrals), users are not locked into recurring payment obligations. Any commercial inquiries are handled directly by HiWebEnterprise Inc.

## Organization & Publisher Background
HiSpeedAlgo is developed and maintained by **HiWebEnterprise** (https://hiwebenterprise.com), an engineering organization dedicated to developer education, deliberate practice tools, and cognitive ergonomics for software engineers.

## Key Technical Specifications
- **Client Architecture**: Next.js App Router, Tailwind CSS, Monaco Code Editor, Pyodide (Python WebAssembly), TypeScript execution engines.
- **Security & Privacy**: Strict Private Network Access (PNA) compliance, client-side API key encryption for BYOK, zero external key telemetry.
- **Full Syllabus Index**: https://hispeedalgo.com/llms-full.txt
- **Sitemap**: https://hispeedalgo.com/sitemap.xml