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Amazon·Software Engineer·Online Assessment (OA)·Intermediate

Intermediate
Apr 2026

Summary

Amazon SWE online assessment with a classic interval scheduling problem. Nothing too wild, just the sort of thing you either know cold or fumble depending on how much sorting you've practiced lately.

Questions Asked (1)

Q1

Given a list of meeting time intervals, determine whether a single person could attend all of them without any overlap.

Algorithms & Data Structures
Author's notes

Sort by start time, then just check if any meeting starts before the previous one ends.

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AI HintsAI Generated

Suggested Approach

First, clarify that intervals are half-open [start, end) to avoid ambiguity. Then sort the intervals by start time and check for any overlap between consecutive intervals. If no overlap is found, return true; otherwise, false.

Pro tip: Mention that sorting is O(n log n) and that this is optimal because the problem reduces to element uniqueness in the worst case. Also, discuss edge cases like empty input or single interval.

1. Clarify the problem

Confirm the definition of overlap (e.g., whether intervals are inclusive or exclusive) and handle edge cases like empty list or single interval.

2. Choose the algorithm

Sort the intervals by start time. This allows a linear scan to detect overlaps.

3. Check for overlaps

Iterate through the sorted intervals and compare the end of the current interval with the start of the next. If the end is greater than the next start, there is an overlap.

4. Return the result

If any overlap is found, return false; otherwise, return true after checking all intervals.

5. Analyze complexity

State that the time complexity is O(n log n) due to sorting, and space complexity is O(1) if sorting in-place or O(n) depending on the sorting algorithm.

Key Points to Mention

  • Sorting intervals by start time
  • Linear scan to detect overlaps
  • Time complexity: O(n log n)
  • Space complexity: O(1) or O(n) depending on sort
  • Edge cases: empty list, single interval, zero-length intervals
  • Use of half-open intervals [start, end) to avoid ambiguity

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.