Three days isn't a lot of time to prepare for a technical interview, but it's enough to meaningfully improve your performance if you focus on the right things. This isn't about cramming every data structure — it's about covering the highest-probability material and showing up confident.
Day 1: Data Structures and Problem Patterns (3–4 hours)
Most coding interviews test a repeating set of patterns. Don't try to cover everything — focus on the highest-frequency topics:
- Arrays and strings: Two pointers, sliding window, prefix sums
- Hash maps: Frequency counting, two-sum variants, grouping
- Trees and graphs: BFS, DFS, basic traversals
- Linked lists: Reversal, cycle detection, merge operations
Solve 2–3 problems per pattern on LeetCode (Easy/Medium). The goal is pattern recognition, not memorization. After each problem, articulate the pattern out loud.
Day 2: System Design Fundamentals (2–3 hours)
For mid-to-senior roles, system design rounds are as important as coding. Cover these basics:
- Horizontal vs. vertical scaling, load balancers, caching layers (Redis, CDN)
- SQL vs. NoSQL — when to use each and why
- API design: REST conventions, rate limiting, auth patterns
- One design walkthrough: Design a URL shortener or a notification system
Practice talking through your design out loud — system design is as much communication as knowledge.
Day 2 (continued): Behavioral Prep (1 hour)
Don't neglect the behavioral component. Prepare 3–4 STAR stories covering: a technical challenge, a cross-team conflict, a time you failed and recovered, and an example of leadership or mentorship. These will come up regardless of company.
Day 3: Mock Practice and Review (2–3 hours)
The most valuable preparation is doing a real practice interview:
- Use Pramp, Interviewing.io, or ask a friend to mock-interview you
- Solve one unseen problem under time pressure, narrating your thinking out loud
- Review 1–2 problems you struggled with on Day 1
- Read the company's engineering blog if they have one — interviewers often ask about real systems they built
What to Do the Morning Of
- Review your STAR stories — not code
- Prepare questions to ask the interviewer
- Test your setup if it's remote (audio, IDE, screen share)
- Eat, sleep, and don't cram — fatigue costs more than one unseen algorithm
The Most Important Skill: Communicating Your Thinking
Interviewers often care more about how you approach a problem than whether you solve it perfectly. Think out loud, state your assumptions, ask clarifying questions, and explain trade-offs. A candidate who talks through a partial solution clearly often beats one who codes silently and submits a working solution.
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