Technical interviews can feel like a trivia contest—until you realize most strong candidates win by thinking clearly under constraints, not by recalling a perfect solution.
The mindset shift: from “solutions” to “skills”
Instead of collecting answers, build repeatable habits you can apply to any problem:
- Clarify the problem first: restate it, confirm inputs/outputs, ask about constraints.
- Explain before you code: outline an approach in plain English or pseudocode.
- Optimize intentionally: start with a correct baseline, then improve time/space if needed.
A simple 4-step framework to use live
When you’re put on the spot, use this structure to stay calm and coherent:
1) Ask constraint questions (30–60 seconds)
Examples:
- “What are the max input sizes?”
- “Are duplicates possible?”
- “Do we care about memory?”
- “What should I return for empty input?”
2) Choose a pattern, not a solution
Most problems map to a handful of patterns:
- Two pointers / sliding window (subarrays, strings)
- Hash maps / counting (frequency, lookups)
- BFS/DFS (graphs/trees)
- Binary search (sorted arrays, monotonic answers)
- Dynamic programming (overlapping subproblems)
Write down why you chose the pattern—interviewers reward reasoning.
3) Narrate as you code
Make your thought process visible:
- State invariants: “My left pointer always points to the start of a valid window.”
- Name variables clearly:
windowSum, seen, bestLen.
- Add quick guard clauses for edge cases.
4) Test with purpose (not just one example)
Before hitting “done,” run:
- Smallest case (empty, size 1)
- Typical case
- Adversarial case (all duplicates, already sorted, negative numbers)
What top candidates do differently
A few high-leverage behaviors that consistently stand out:
- They trade off out loud: “This is O(n) time, O(n) space; we can reduce memory by…”
- They recover smoothly: if stuck, they say what they’ve tried and propose a next step.
- They keep the loop tight: correct → test → optimize → re-test.
A practical weekly prep plan (60–90 minutes/day)
- 3 days: 2 problems/day from one pattern (e.g., sliding window)
- 1 day: review + rewrite one solution from memory (focus on clarity)
- 1 day: timed mock (45 minutes) + reflection notes
- 1 day: system/design-lite discussion prompts (APIs, caching, tradeoffs)
Discussion: What part of technical interviews is hardest for you right now—coming up with the approach, coding cleanly under pressure, or explaining your thinking—and what have you tried so far?