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Amazon SDE Interview

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Updated: 2026-09-24

This note is a first-person account of one Amazon SDE-1 interview round. The round ran about an hour online through Amazon Chime and mixed one algorithm problem with a few system design questions and questions about the Leadership Principles. The useful part is the mistakes. The author picked a heap where binary search was the better fit, wrote code with redundant variables, answered system design too generically, and told Leadership Principle stories without the STAR format. Each mistake comes with the lesson it produced and the fix. A short keys to success list closes the note. The closing checklist names the topics worth drilling before the call. It lists binary search, heap, and two pointers. Practice each until you can code it without notes. Read the mistakes first, then use the lessons as a checklist for your own preparation.

Round 1 - SDE-1

Overview

  • Duration: ~1 hour
  • Format: Online via Amazon Chime
  • Content:
    • 1 algorithm problem
    • A few System Design questions
    • Questions about the Amazon Leadership Principles

Common Mistakes and Lessons

Binary Search & Edge Cases

  • Mistake: Chose a Heap instead of Binary Search for finding the k smallest elements across 2 sorted arrays
    • Heap: O(k log k)
    • Binary Search: O(log(min(len(A), len(B))))
  • Lessons:
    • Review Binary Search thoroughly, including edge cases on sorted arrays
    • Ask the interviewer to clarify the approach before coding

Code Quality

  • Mistake: The code had many redundant variables and was not optimized
  • Lessons:
    • Use clear variable names
    • Write an optimal algorithm
    • Review the code before running it

System Design

  • Mistake: Answered too generically, mentioning only REST API and missing key elements
  • Lessons: When answering System Design, mention:
    • Scalability
    • Caching (Redis)
    • Indexing (ElasticSearch)
    • Load balancing
    • Explain the logic clearly and simply

Leadership Principles

  • Mistake: Answers were incoherent and did not use the STAR format
  • Lessons:
    • Use the STAR format (Situation - Task - Action - Result)
    • Amazon evaluates both technical skills and working mindset
    • Prepare your stories in STAR form ahead of time

Keys to Success

  • Be fluent in: Binary Search, Heap, Two Pointers
  • Write clean, optimized code and re-read it before running
  • System Design: mention scalability, caching, indexing
  • Leadership Principles: prepare thoroughly with the STAR format

See also: Coding Interview Resources · Interview Senior Engineer · Oracle Interview Gandhinagar