February 2026 · 9 min read
DSA Interview Questions: What to Study and How to Prepare (2026)
Data structures and algorithms form the backbone of most technical interviews at top tech companies. Here's a fact-checked guide to the topics that actually show up — and how to prepare without burning out.
If you're aiming for roles at Google, Amazon, Meta, or other top tech companies, you'll almost certainly face at least one round of coding questions that test data structures and algorithms (DSA). Interviewers aren't trying to stump you with obscure topics — they focus on a core set of structures and patterns that appear again and again. This guide breaks down which DSA topics show up most often in real interviews, how to prioritize your study time, and how to pair DSA practice with company-specific interview prep and mock interviews so you're ready for the full loop.
Why DSA Matters in Tech Interviews
Companies use DSA rounds to assess problem-solving, code clarity, and communication under time pressure. The topics tested are largely consistent across FAANG and similar firms: arrays, strings, hash maps, trees, graphs, and dynamic programming appear in most coding interviews. Curated lists like the Blind 75 (75 problems) and NeetCode 150 (150 problems) exist because they reflect this reality — a relatively small set of patterns covers a large share of what you'll see. Learning by pattern (e.g. sliding window, two pointers, BFS/DFS) is more efficient than grinding random problems, and pairing that with knowledge of how each company runs its process and what timeline to expect gives you a clear preparation path.
Foundation Topics (Master First)
These show up in almost every technical interview and should be your first focus. Arrays and strings are the most common starting point: subarray problems, two pointers, sliding window, and prefix sums appear frequently. Hash maps and hash sets are used for fast lookups and counting (e.g. two sum, anagrams, first non-repeating character). Stacks and queues appear in parsing, level-order traversal, and design problems. Binary search isn't just for sorted arrays — interviewers often ask variants on answers or ranges. Recursion and basic time/space complexity analysis are expected; you should be able to state Big O for your solution and discuss trade-offs. If you're targeting Google or Meta, nailing these foundations is non-negotiable before moving to harder topics.
Intermediate Topics (Most Frequently Asked)
Once foundations are solid, prioritize these. Binary trees and BSTs — traversals (inorder, preorder, postorder, level-order), height/depth, path sums, and validation — are extremely common. Linked lists show up in merge, reverse, cycle detection, and reordering problems. Graphs are tested via BFS/DFS, connectivity, and path finding; many interview questions are graph problems in disguise. Heaps and priority queues appear in "top K" and merge-k-sorted type questions. Backtracking (subsets, permutations, combinations) and basic dynamic programming (fibonacci-style, knapsack, longest increasing subsequence, grid paths) round out the intermediate tier. Companies like Uber, Netflix, and Airbnb ask a mix of these; our company interview questions pages list the kinds of problems each company tends to emphasize.
Advanced Topics (When You Have Extra Time)
Not every interview goes here, but senior or specialized roles may. Advanced dynamic programming (state compression, digit DP) and advanced graph algorithms (Dijkstra's, Bellman-Ford, topological sort, union-find) appear in some loops. Tries are common for string/prefix problems; monotonic stacks and queues show up in array optimization questions. If you've completed a list like NeetCode 150 and have time, adding these will broaden your coverage. For most candidates, though, mastering the foundation and intermediate topics plus system design and behavioral prep is enough — don't delay mock interviews or company research to chase every advanced topic.
How Many Problems Should You Do?
There's no single magic number. The Blind 75 is a proven minimal set: 75 problems that cover the most frequent patterns. The NeetCode 150 expands to 150 problems with video explanations and is widely used as a standard target. Many candidates aim to complete at least one of these lists and then do a few company-tagged or pattern-specific problems before their interview. Quality matters more than quantity: understanding why a solution works and being able to code it cleanly under time pressure beats having done hundreds of problems superficially. Combine problem practice with platforms that teach by pattern, and use our Google, Amazon, and Meta question guides to see which patterns each company tends to ask.
Patterns Over Memorization
Interviewers care more about your approach than whether you've seen the exact problem. Patterns like two pointers, sliding window, binary search on answer, BFS/DFS, and memoization/DP state recur across many questions. When you practice, name the pattern you're using and think about how you'd explain your reasoning in an interview. This is where AI mock interviews and peer mocks (e.g. Pramp, Interviewing.io) help — they simulate the communication and follow-up questions you'll get. Also review coding interview books if you prefer learning from a structured curriculum; many align with the same patterns and topics above.
How to Combine DSA with the Rest of Your Prep
DSA is one part of the loop. Google, Amazon, and others also run behavioral rounds, system design (for mid/senior), and sometimes domain-specific or debugging rounds. Allocate time for DSA (e.g. daily problems or a curated list), but also for company-specific question lists and process guides so you know round count, timeline, and what to expect. In the 2–4 weeks before your interview, add mock interviews to practice explaining your approach and handling hints. That combination — DSA patterns, company research, and mocks — is more effective than only grinding problems.
Bottom Line
Focus on foundation topics first (arrays, strings, hashing, two pointers, sliding window, stacks, queues, binary search), then intermediate (trees, graphs, linked lists, heaps, backtracking, basic DP). Use a curated list like Blind 75 or NeetCode 150 to avoid random overload. Learn patterns, not just solutions, and pair DSA practice with company-specific guides and mock interviews. When you're ready to test yourself in a realistic setting, try an AI mock interview tailored to your target company.
Frequently Asked Questions
What DSA topics are most important for coding interviews?
Arrays, strings, hash maps, two pointers, sliding window, stacks, queues, binary search, and recursion form the foundation. Trees (binary trees, BSTs), graphs (BFS/DFS), linked lists, heaps, backtracking, and basic dynamic programming are the most frequently asked intermediate topics. Master these before spending time on advanced topics.
Is Blind 75 or NeetCode 150 enough for FAANG?
Blind 75 (75 problems) covers the essential patterns; NeetCode 150 (150 problems) gives broader coverage with video explanations. Many candidates use one of these as a core list and supplement with company-tagged problems and mock interviews. You also need behavioral and, for senior roles, system design prep — use our Google and Amazon guides for full coverage.
How do I prepare for DSA without memorizing?
Focus on patterns: two pointers, sliding window, binary search, BFS/DFS, and DP state/memoization. When solving, name the pattern and explain your reasoning. Practice with timed mocks (e.g. AI mock interviews or peer mocks) so you get used to communicating under pressure.
Do I need to know advanced algorithms like Dijkstra for interviews?
It depends on the company and level. Basic graph traversal (BFS/DFS) is common; Dijkstra and topological sort appear in some interviews. Prioritize foundation and intermediate topics first; add advanced graph or DP topics if you have time and are targeting roles that emphasize them.
How should I combine DSA practice with company-specific prep?
Use a curated DSA list (Blind 75 or NeetCode 150) for daily pattern practice. In parallel, read our interview questions and process guides for your target companies to see what topics they emphasize. Add mock interviews 2–4 weeks before your loop to practice communication and timing.