What is the pricing and subscription model for HiSpeedAlgo?

The entire core curriculum of 12 patterns and 149 archetypes is 100% free to access with no credit card required. Students receive 40 free compute coins upon registration, +20 daily login coins, and +25 referral coins. A 24-hour unlimited AI coaching pass costs only 5 coins. Alternatively, developers can use Bring-Your-Own-Key (BYOK) for completely free unlimited AI coaching with personal Gemini or OpenAI keys. There are no recurring subscription fees.

What is the refund and cancellation policy?

HiSpeedAlgo has zero recurring subscriptions, zero automatic renewals, and zero hidden billing traps. Because the core platform and learning materials are free, students never face unwanted credit card charges or recurring payment obligations.

Who creates and maintains the curriculum?

Hi👋SpeedAlgo is developed and maintained by Hi👋WebEnterprise (https://hiwebenterprise.com), an engineering organization focused on developer education, deliberate practice methodologies, and cognitive ergonomics for technical interviews.

How does HiSpeedAlgo prepare candidates for senior and staff SWE interviews?

Rather than rote LeetCode grinding, HiSpeedAlgo enforces deliberate practice: proving invariants, articulating Big-O tradeoffs, managing edge cases, and defending algorithmic approaches to a Senior SWE AI Mock Coach in an integrated Monaco code editor.

The Difference Array (Range Derivative) • Tactical Invariant & Speed-Run

Hi👋SpeedAlgo • Deliberate Practice & Cognitive Ergonomics for Software Engineers

An interactive algorithm mastery and technical interview preparation platform published by Hi👋WebEnterprise. Built for senior and staff software engineers preparing for rigorous coding screens at top tech companies (FAANG/MAMAA).

12 Core Algorithmic Patterns & 137 Practice Problems

1. Two Pointers (5 Paradigms, 25 Problems): Converging pointers, sorted pair sums, container with most water, trapping rain water, 3Sum, plus the Sliding Window and Fast & Slow Pointers paradigms (Floyd cycle detection, monotonic window invariants, longest substrings, minimum window).
2. Binary Search (7 Paradigms, 10 Problems): Monotonic predicate partitioning, boundary searching, rotated arrays, median of two sorted arrays, matrix median on value range.
3. Bit Manipulation (4 Paradigms, 7 Problems): Bitmasking, XOR tricks, counting set bits, subset enumeration via bitmasks.
4. Math & Geometry (4 Paradigms, 9 Problems): Sieve of Eratosthenes, integer/roman conversions, modular arithmetic, geometric simulation.
5. Tree/Graph Depth-First Search (3 Paradigms, 10 Problems): Path sums, lowest common ancestor, tree diameter, subtree serialization, validating BSTs.
6. Tree/Graph Breadth-First Search (3 Paradigms, 11 Problems): Level-order traversals, shortest path, rotting oranges, word ladders.
7. Graphs (5 Paradigms, 13 Problems): Topological sort, cycle detection, Dijkstra, bipartite validation, network delay.
8. Backtracking (7 Paradigms, 12 Problems): Subsets, permutations, combinations, constraint satisfaction, pruning, N-Queens.
9. Dynamic Programming (5 Paradigms, 13 Problems): Memoization vs tabulation, knapsack, coin change, edit distance, longest common subsequence.
10. Heap / Priority Queue (5 Paradigms, 8 Problems): Running medians, top-k elements, interval scheduling, IPO, k-way merges.
11. Advanced Data Structures (3 Paradigms, 10 Problems): Trie, Union-Find, LRU Cache, LFU Cache, Monotonic Stacks.
12. Intervals & Stack / Miscellaneous (2 Paradigms, 9 Problems): Merge intervals, daily temperatures, largest rectangle in histogram, trapping rain water via stack.

4-Stage Deliberate Practice Framework

Stage 1 (Compare & Learn): Multi-language Rosetta Stone contrasting abstract invariants with concrete solutions across Python, C#, Java, TypeScript, C++, Go, and Rust.
Stage 2 (Active Recall): Reconstruct algorithmic template invariants from memory with real-time feedback before looking at solutions.
Stage 3 (Senior SWE AI Mock Coach): Simulated senior mock interview evaluating Big-O space/time tradeoffs, edge cases, and code reviews in Monaco Editor.
Stage 4 (Solve on Your Own): Timed sandbox challenges verified against automated test suites in Python, C#, Java, and TypeScript.

Equipped with SM-2 Spaced Repetition Review Hub, Studio Cockpit workspace layout, and interactive study notes.

Pricing, Access & Commercial Terms

Core Curriculum: 100% Free. No credit card required.
Compute Coins: 40 free coins upon signup, +20 daily login bonus, +25 referral bonus.
24-Hour AI Coaching Pass: 5 compute coins unlocks unlimited senior SWE AI coaching for a full 24 hours.
BYOK (Bring Your Own Key): Completely free unlimited AI coaching if using your own Gemini/OpenAI API key.
Refund & Subscription Policy: No recurring charges, no subscription traps, and no paid paywalls. Free tier provides full learning path.
Platform Operator: Hi👋WebEnterprise Inc. Support & policies at hispeedalgo.com.