DSA Crash Course
Interview Simulation

Interview Simulation — Overview

Mark when done:

Phase 6 -- Interview Simulation (Days 57-60)

Deep Dive: The Interview is a Performance, Not Just Code

Beginner tip: Technical interviews test communication as much as coding. The biggest mistake is jumping straight to code. Instead: clarify the problem (2 min), state your approach out loud (2 min), code while talking (18 min), then test with examples (5 min). Interviewers WANT to help you -- but they can only help if you think out loud.

The 35-Minute Breakdown

Minutes 0-3:   CLARIFY
  "Can nums be empty?" "Are values always positive?" "Is it sorted?"
  -> Shows you don't jump to code blindly.

Minutes 3-5:   IDENTIFY PATTERN
  "This looks like a sliding window problem because we need the
   longest contiguous subarray with a constraint."
  -> Shows pattern recognition.

Minutes 5-7:   PROPOSE + COMPLEXITY
  "I'll use a variable-size sliding window. O(n) time, O(k) space.
   The brute force would be O(n^2)."
  -> Shows you considered alternatives.

Minutes 7-25:  CODE (the actual implementation)
  Write CLEAN code. Use meaningful names. Talk while coding.
  "I'm initializing left pointer... now expanding right..."

Minutes 25-30: TEST
  Trace through your code with the example: "At i=0, window is..."
  Try an edge case: empty input, single element, all same values.

Minutes 30-35: OPTIMIZE (if asked)
  "We could optimize space by using X instead of Y."

Common Mistakes That Cost Offers

1. Jumping to code without clarifying -> miss constraints
2. Not stating brute force first -> miss opportunity to show thinking
3. Silent coding -> interviewer cannot give hints if they don't know your process
4. Not testing -> bugs in untested code lose more points than slow solutions
5. Panicking on stuck -> say "Let me think about this differently" and try a new angle

The Stuck Protocol

Stuck for 2 min? -> Re-read the problem. Look for missed constraints.
Stuck for 5 min? -> Try a different pattern. Say it out loud.
Stuck for 8 min? -> Simplify. Solve a smaller version first.
Stuck for 10 min? -> Ask: "Could you give me a hint on the approach?"
  (Asking for a hint is better than sitting in silence.)

Mock Interview Log

#DateProblemsTimeResultWhat Went WellWhat to Improve
145 min
245 min
345 min
445 min
545 min
645 min

Interview Execution Framework

MINUTE 0-3:   CLARIFY (constraints, edge cases, input size)
MINUTE 3-5:   THINK ALOUD (identify pattern, discuss approach)
MINUTE 5-7:   PROPOSE (state approach, time/space complexity)
MINUTE 7-25:  CODE (clean, modular, well-named)
MINUTE 25-30: TEST (trace through examples, edge cases)
MINUTE 30-35: OPTIMIZE (can we do better?)

Behavioral STAR Stories

Two examples filled in below cover the two most common FAANG behavioral themes. Use them as a template — replace the Situation, Task, Action, Result with your own real stories. Keep each ≤ 90 seconds out loud (≤ 200 words written).

#ThemeSituationTaskActionResultMaps to (LP/Value)
1Disagreed with a teammate on technical approachOur team was building a new search index. The senior dev wanted to use Elasticsearch; I felt our scale didn't justify the operational cost and proposed Postgres full-text search instead.Reach a decision the team would commit to before the next sprint planning.I built two prototypes over a weekend — one in Postgres FTS, one in Elasticsearch — measured indexing time, query latency at our 10k-doc scale, and operational footprint. Wrote a 1-page comparison and walked the team through the trade-offs.Team chose Postgres for v1 (saved ~$400/mo + a week of ops setup). Agreed to revisit if we hit 1M docs — which we did 14 months later, and the migration was clean because we'd documented the trigger criteria.Amazon: Have Backbone, Disagree and Commit · Google: Strong Opinions, Loosely Held
2Delivered under a tight deadlineTwo days before a customer demo, our auth integration broke after an upstream API deprecation.Restore login flow without rolling back unrelated features that were also in the release.I scoped the failure (only the OAuth refresh path), wrote a 30-minute hotfix wrapping the deprecated call with the new signature, added a 5-minute regression test, paired with QA to validate the demo path, and documented the rollback procedure in case it failed. Shipped 18 hours before demo.Demo went off without users noticing. Spent the following sprint replacing the wrapper with a proper migration to the new auth API.Amazon: Bias for Action, Ownership · Meta: Move Fast
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Tip: map each story to multiple LPs — most stories naturally cover 2-3. Practise the same story in 60 seconds and 90 seconds; interviewers gauge time-management.

Target Companies

CompanyApplied?StatusCodingSystem DesignBehavioralNotes
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Notes


External Resources (Hand-Picked Supplements)

  • interviewing.io — anonymous mock interviews with real engineers. The replays of past interviews (free) are the closest thing to watching a senior candidate's actual thought process.
  • Pramp — peer-to-peer mock interviews; trade slots with other candidates. Use 2-3 sessions during Days 57-59.
  • Tech Interview Handbook — Behavioral Questions — STAR-formatted templates and the most-asked behavioral prompts at FAANG companies. Use to fill in the (currently blank) STAR table in this README.
  • Amazon Leadership Principles — official — required reading if Amazon is on your target list. Map at least one STAR story per principle.
  • System Design Primer — for the Day 59 system-design overview. Read the "Latency comparison numbers" and "Common solutions" sections at minimum.