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

Intermediate
Jun 2026

Summary

Amazon OA for a SWE role, just one algorithmic problem about truck packing. Pretty clean problem statement but the constraints make it trickier than it first looks.

Questions Asked (1)

Q1

Given a list of parcel counts per product category, a truck capacity, and a per-product-type load limit per truck, find the minimum number of trucks needed to ship everything.

Algorithms & Data Structures
Author's notes

I stared at this for a bit before realizing the two constraints interact in a non-obvious way.

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AI HintsAI Generated

Suggested Approach

Clarify the problem constraints and edge cases first, then model it as a bin packing problem with per-item type constraints. Discuss greedy heuristics and potential exact algorithms, analyzing trade-offs in time complexity and optimality.

Pro tip: Mention that while the problem is NP-hard, in practice Amazon uses efficient heuristics with guarantees, and always validate with test cases including edge cases like zero counts or capacity smaller than a single item.

1. Clarify requirements and constraints

Ask about input size, whether items of the same category can be split across trucks, and if there are any other constraints like truck capacity being uniform.

2. Formalize the problem

Define it as a bin packing variant where each bin has a capacity and a per-category limit; identify it as NP-hard and discuss implications.

3. Propose a solution approach

Outline a greedy algorithm (e.g., first-fit decreasing) and an exact approach (e.g., integer programming or branch-and-bound) with complexity analysis.

4. Analyze trade-offs and edge cases

Compare time vs. optimality, discuss when greedy suffices, and mention handling of edge cases like zero counts or infeasible limits.

5. Test and validate

Walk through a small example to verify the algorithm and discuss how to test with random and adversarial inputs.

Key Points to Mention

  • NP-hardness of bin packing and its implications
  • Greedy heuristics like first-fit decreasing and their approximation ratios
  • Exact algorithms such as integer linear programming or branch-and-bound
  • Time and space complexity analysis
  • Edge cases: zero counts, capacity smaller than a single item, per-category limit constraints
  • Scalability considerations for large inputs

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