The complete hub for coding interview prep in 2026. Pattern deep-dives, drill-grade practice, and an AI copilot that runs invisibly during your real interview rounds. From two-pointer to system design, in one place.
Two-pointer, sliding window, BFS/DFS on graphs, tree traversal, dynamic programming, binary search. Master these and you'll recognize the underlying structure of most coding interview problems.
Each pattern has its own subpage and supporting blog post — the full pattern explanation, the standard subproblems, and 5-10 representative LeetCode problems.
The real coding interview is voice + code, not silent typing. Drill with the AI coach that grades your explanation, structure, and timing — not just correctness.
When the real interview happens, the same coach runs in live mode — sub-second answer drafting, invisible to screen recording, native on Mac & Windows.
Python, JavaScript, TypeScript, Java, C++, C#, Go, Rust, Swift, Kotlin, Ruby. Standard-library calls and idiomatic patterns calibrated per language.
Your drill experience transfers literally to the real interview — same model, same answer style, same patterns. The hardest skill in coding interviews — recognizing the pattern fast — gets trained directly.
FAANG-tier coding interviews ask harder problems, not different patterns. Once you recognize the pattern underneath a problem, the implementation is mostly mechanical. Here are the five that come up most.
Optimal substructure + overlapping subproblems. The hardest-to-recognize pattern but the most rewarding when you nail it. Deep-dive →
Two pointers traverse an array; sliding window maintains a contiguous subrange. Subtle but ubiquitous. Deep-dive →
BFS, DFS, topological sort, shortest-path, union-find. Most networking and connectivity problems. Deep-dive →
Traversals (DFS / BFS), recursion, depth, lowest-common-ancestor. Underpins many DP-on-trees problems. Deep-dive →
Search in O(log n), monotonic predicates, search-on-answer-space. Underrated but appears constantly. Deep-dive →
L5+ rounds. Frameworks, tradeoffs, scaling. See the system design hub →
Most candidates over-rotate on problem count and under-rotate on pattern recognition. Here’s a calibrated prep approach that wins at FAANG tier.
Deeper roadmap: FAANG 30-day roadmap. The full pattern list: Top 10 LeetCode Patterns. For busy engineers: tech-interview prep checklist.
| Dimension | Average | Great |
|---|---|---|
| Pattern recognition | Solves but takes 10+ min to start | Names the pattern in under 60 sec |
| Explanation while coding | Silent solve, narrates after | Narrates in real-time |
| Edge cases | Caught when interviewer asks | Listed up-front before coding |
| Time management | Runs over on hard problems | Time-boxes, gracefully pivots |
| Communication | Heads-down on the keyboard | Reads interviewer reactions, adapts |
Different companies use different platforms. PhantomCode’s coding copilot works on all of them — it’s a native desktop app, not a browser extension.
More on the live coding copilot: AI Coding Interview Assistant.
Five patterns cover ~80% of FAANG-tier coding interview problems: dynamic programming, two-pointers / sliding window, graph algorithms (BFS/DFS/topological sort), tree algorithms, and binary search. Add system design for L5+ roles. Cover those deeply and you'll recognize the underlying structure of most questions you'll see.
For working engineers with solid fundamentals, 30 days of focused prep covers FAANG-tier rounds. Beginners need 8-12 weeks. The right answer depends on how many full mock interviews you complete — aim for 10+ voice-paced timed mocks, not just question count.
Practicing silently. Reading question lists and solving problems alone builds knowledge but not delivery. The real interview is a conversation — interviewer asks, you explain. Candidates who only practice silently freeze in real rounds because they've never rehearsed the talking-while-thinking skill.
AI tools that run candidate-side (like PhantomCode) operate as candidate-side coaches — analogous to having notes or a coach. The line is drawn at proctored, NDA-bound assessments. PhantomCode is built specifically for live coding rounds and stays invisible to screen recording on every major platform.
Pick the language you write fastest in. Python is the most common at FAANG because it's terse and lets you focus on algorithm. Java and C++ are also strong choices, especially for L5+ roles where performance trade-offs matter. PhantomCode supports 11 languages with idiom-matching for each.
Mock-mode practice transfers directly to live mode — same coach, same patterns, same answer style.
Start drillingDownload now — invisible, undetectable, and works on every platform. Plans start at $19.