How to Prepare for a Technical Interview
What a Technical Interview Loop Actually Looks Like
Before you can prepare, you need to know what you're preparing for. Most technical loops at mid-to-large companies include:
- Coding rounds (1–2): Algorithmic problems, usually on a shared editor. Expect arrays, trees, graphs, dynamic programming, and string manipulation.
- System design round (1): Open-ended architecture questions — "Design Twitter" or "Design a URL shortener." More common at senior+ levels.
- Behavioral round (1): Leadership principles, conflict stories, project deep-dives.
- Technical deep-dive or domain round (optional): Relevant for specialized roles — ML, infra, mobile.
Knowing the format stops you from over-indexing on one area while ignoring others.
How to Prepare for a Technical Interview in 4 Weeks
This assumes you're 4 weeks out. Compress or expand based on your timeline.
Week 1 — Foundations
Cover the data structures and algorithms you're weakest on. If you haven't used a heap or a trie in years, don't skip them hoping they won't appear.
Focus areas:
- Arrays, strings, hash maps
- Linked lists, stacks, queues
- Trees and graphs (BFS, DFS)
- Sorting and searching
Do 2–3 easy and medium problems per day. Don't chase hard problems yet — build pattern recognition first.
Week 2 — Pattern Drilling
Most coding problems fit a small set of patterns: sliding window, two pointers, fast/slow pointers, merge intervals, top-K elements, binary search on answer. Once you recognize the pattern, the solution becomes mechanical.
Practice by pattern, not by random problem. Pick a pattern, do 3–5 problems in it, then move on.
Week 3 — System Design + Mock Practice
Shift half your time to system design. Learn the core building blocks: load balancers, caches, databases (relational vs. NoSQL), message queues, CDNs. Practice structuring a 45-minute design answer out loud — requirements → high-level design → deep-dives → trade-offs.
The other half: time yourself on coding problems under realistic conditions. Set a 35-minute timer. No hints.
Week 4 — Weak Spots + Behavioral Prep
Spend this week on whatever your mock sessions revealed. Also prep your behavioral stories using the STAR format (Situation, Task, Action, Result). Have 5–6 strong stories ready — they'll cover most behavioral questions across any company.
The Most Common Prep Mistakes
Mistake 1: Grinding problems without reviewing your misses. After every failed problem, write down why you missed it and what pattern you needed. Reviewing that log is more valuable than doing 20 more problems.
Mistake 2: Skipping the communication layer. Interviewers score your thought process, not just your final code. Practice narrating as you type. If you code silently, you're leaving points on the table.
Mistake 3: Ignoring behavioral prep until the last minute. Behavioral rounds eliminate candidates just as often as coding rounds. Prep them in parallel.
Mistake 4: Treating system design as optional. Even at mid-level, some companies include a design component. Don't be caught unprepared because you assumed it was only for seniors.
How to Use the Last 48 Hours
Don't cram new material. Instead:
- Re-read your mistake log — reinforce patterns you missed.
- Do one or two easy warm-up problems to stay sharp.
- Review the company's engineering blog or recent talks — shows genuine interest and gives you talking points.
- Sleep. Cognitive performance under pressure degrades sharply with poor sleep.
Practice This Now
Reading a prep plan is not the same as doing reps under pressure — the only thing that matters is how you perform live.