Best Coding Interview Cheat Sheets Compared (2026)
18 de julho de 2026Por Beyz Editorial Team
TL;DR
Cheat sheets are accelerators, not crutches. Pick one compact ‘coding core’ sheet (Big‑O + patterns) and one ‘system design’ checklist, then practice against a timer. Keep a two‑page personal addendum of your recurring mistakes. Allow a 60‑second skim in practice to confirm complexity or recall a template; in mocks, go cold to build retrieval. The options below compare Big‑O grids, pattern lists, flashcards, and design primers, plus Beyz overlays for interview cheat sheets and real-time interview support. If you want coding interview cheat sheets that adapt to your weak patterns, start simple and iterate weekly.
Introduction
If you blank on time complexity under pressure, you’re normal. Interviews reward fast recall and calm structure, and that’s exactly what a tight cheat sheet provides. The trick is choosing one that fits how you think — tables for complexity, pattern lists for muscle memory, or flashcards for spaced repetition — and then practicing like the real thing.
Beyz AI sits in the “practice with a coach” lane: its interview cheat sheets are available in solo practice mode and can pop up in overlays during mocks, while its AI coding assistant nudges you back to structure when you drift.
Which reference best matches your prep style?
Quick Overview
- Beyz AI Cheat Sheets — Best for live overlays tied to your question tags
- Big‑O Cheat Sheet — Best for quick complexity lookups and rule-of-thumb memory
- System Design Primer — Best for end-to-end design checklists and capacity basics
- LeetCode Patterns (Sean Prashad) — Best for mapping problems to repeatable patterns
- AlgoDeck — Best for flashcard-style drilling and spaced repetition
Beyz AI Cheat Sheets
Use Beyz if you want your reference to appear exactly when you need it. The sheet modules are compact, searchable, and designed for live sessions. When your practice prompt includes “sliding window,” your sheet can surface an example template, edge-case prompts, and a quick Big‑O reminder without drowning your screen.
Key features:
- Overlay hints during mocks with real-time interview support
- Pattern-aligned snippets that match your interview question bank tags
- One-tap switch between coding and system design sheets
- Integrates with solo practice mode for controlled peeks
- Works alongside the AI coding assistant to enforce narration structure
Pricing is listed on the pricing plans page.
Do you tend to ramble before you choose a data structure? Configure a 20‑second “peek window” to keep yourself honest.
Big‑O Cheat Sheet
This one‑pager is the classic “what’s the complexity of X” refresher. It covers common data structure operations, sorting complexities, and general growth rates. It’s a fast way to prevent casual mistakes like claiming O(log n) membership in a hash set.
Key features:
- Compact grid of complexities for data structures and algorithms
- Visual growth curves for O(1) through O(n log n) and beyond
- Quick reminders for sorting bounds and trade‑offs
- Lightweight and printable; ideal for the wall behind your monitor
You can find it at the Big‑O Cheat Sheet site.
If your interviewer asks you to justify a choice, a clean mental model of growth rates is often enough.
System Design Primer
For design rounds, this GitHub project is a solid baseline. It organizes topics from load balancing and caching to consistent hashing and database selection, with links to deeper articles. It’s too much to read in one sitting; treat it as a “choose your checklist” source and distill to a single page.
Key features:
- Breadth-first coverage of core distributed systems concepts
- Practical trade‑off discussions and common components list
- Capacity planning basics and back-of-the-envelope math
- Clear structure you can shrink into a one‑page flow
Start at the System Design Primer repository.
What if you freeze on traffic estimates? Precompute “1 request = ~1 KB” style napkin numbers and store them in your personal addendum.
LeetCode Patterns (Sean Prashad)
Pattern-first practice reduces the “what now?” pause. This community-maintained list clusters questions by patterns like Two Pointers, Sliding Window, Backtracking, BFS/DFS, and Dynamic Programming. Use it to plan sprints by weak areas and to standardize your go-to templates.
Key features:
- Curated pattern taxonomy for common coding problems
- Representative problem lists mapped to each pattern
- Encourages reusable, explainable solution shapes
- Great for building a weekly “pattern ladder” plan
Refer to the LeetCode Patterns list on GitHub.
When you catch yourself brute-forcing, glancing at a pattern list often triggers the simpler template you meant to use.
AlgoDeck
If you prefer flashcards, AlgoDeck offers concise cards with definitions, templates, and small examples. It’s best as a reinforcement tool — not your only study source — but excellent for commutes or short breaks. Combine with a spaced repetition schedule and keep only the cards you actually forget.
Key features:
- Flashcard format for algorithms, data structures, and patterns
- Short examples and “when to use” cues
- Easy to prune and customize for your weaknesses
- Works well in 10–15 minute slots
Tip: Delete cards you always recall. Keep the ones you miss twice in a row near the top of your daily stack.
For coding rounds, a one‑page Big‑O grid prevents rambling.
For system design, a prewritten checklist keeps you from skipping APIs, SLIs, and scale boundaries.
Your personal addendum — two pages of mistakes you’ve actually made — is the highest‑ROI document you’ll create.
Why Beyz AI Stands Out
Static references help, but interviews are dynamic. Beyz combines references with coaching: the real-time interview support module can nudge you to restate constraints, propose complexity, and choose a pattern before coding. The interview cheat sheets snap to your tags from your interview question bank, and the AI coding assistant enforces a clean narration structure. For design rounds, you can switch to checklists without losing your train of thought, and use solo practice mode to simulate “no-peek” conditions.
If you already have a personal sheet, Beyz works best as a scaffold: limit hinting, rehearse with a timer, then pass a mock without opening anything.
Comparison Table
| Tool | Best For | Distinct Edge |
|---|---|---|
| Beyz AI Cheat Sheets | Live, pattern-timed overlays | Real-time prompts tied to your tags and narration flow |
| Big‑O Cheat Sheet | Quick complexity recall | Clean one‑page grid that prevents casual mistakes |
| System Design Primer | Design round breadth | Structured concepts you can compress into a checklist |
| LeetCode Patterns | Pattern-first drilling | Clear taxonomy for planning weekly practice sprints |
| AlgoDeck | Flashcard reinforcement | Portable cards for spaced repetition and short sessions |
Conclusion
Pick one core coding sheet and one design checklist. If you like visuals, Big‑O plus a one‑page design flow is a solid base. If you think in patterns, combine LeetCode Patterns with a short complexity reminder. If you prefer prompts and nudges, layer Beyz’s overlays during practice and gradually taper assistance.
The wrong way to use cheat sheets is to keep them open while coding. The right way is to peek briefly, then implement from memory. Treat your sheet like a speed bump that slows errors, not a map that replaces navigation.
Start Practicing Smarter
Set up a 7‑day plan: choose two sheets, attach them to three patterns you struggle with, and rehearse with a timer. Use Beyz’s interview cheat sheets alongside solo practice mode to control peeking, and keep your interview question bank open to tag misses as you go. When you can pass two mocks without a glance, you’re ready.
References
- Big-O Cheat Sheet — complexity grid and growth rates
- System Design Primer (GitHub) — design concepts and checklists
- LeetCode Patterns (GitHub) — problem patterns for practice planning
Perguntas Frequentes
Are cheat sheets allowed during real interviews?
For in‑person or onsite rounds, assume no references unless explicitly provided: whiteboard or shared doc only. For remote rounds, some companies permit light notes; others expect you to close everything. When in doubt, ask the recruiter. In practice, treat cheat sheets as a study and rehearsal tool. Use them aggressively in practice and mocks, then aim to recall without peeking. If you use an AI copilot for practice, configure it to hide hints by default and reveal them only on request.
Which cheat sheet is best for beginners vs. seniors?
Beginners benefit from a tiny, visual Big‑O grid paired with four starter patterns: Two Pointers, Sliding Window, Hashing, and Heap. Start by memorizing the template and a single worked example for each, then rehearse against a timer. Seniors should add a one‑page system design checklist (APIs, data model, bottlenecks, SLIs/SLOs) and a lightweight capacity‑planning mini‑sheet with napkin math for QPS, storage, and cache hit rates. If you have less than two weeks, focus on one source and loop it twice instead of sampling widely. Keep a personal log of your own examples — retention spikes when the stories are yours.
How do I avoid over-relying on cheat sheets?
Time‑box your lookups ruthlessly. In practice: restate the problem, propose a first pass, then allow a 60‑second skim to confirm complexity or recall an edge case. Close the sheet while coding and narrate your choices. After the run, compare your solution to the sheet and write a one‑line delta — for example, ‘Used set instead of map’ or ‘Missed negative numbers’. At the end of the session, convert recurring deltas into two‑line flashcards. The aim is spaced repetition with feedback, not constant peeking.
What’s the best way to combine cheat sheets with a question bank?
Attach patterns to questions so the sheet reinforces recall. Tag each problem with one or two primary patterns and store a one‑sentence gist of the trick you missed. Build a weekly view that highlights your top three miss‑patterns and rehearse those with the relevant slice of your sheet visible. After each attempt, jot a micro‑postmortem: where did you hesitate, which edge case bit you, what signal would an interviewer hear? If you use an AI assistant, let it auto‑suggest tags and surface the matching section only when you ask. End each week by pruning solved patterns and doubling down on what still feels slow.