Amazon Interview Questions — Page 75

Amazon·Software Engineer·Onsite - Coding / Algorithms

May 2026

Amazon SWE coding round, one problem the whole time. It was a string/permutation thing that sounds straightforward but has some real complexity hiding in it once you start thinking about how to count substrings efficiently.

You have a password string of length n. An attack sequence is given as a permutation of positions, and at each second t, the character at that position gets replaced with '*'. The password is considered irrecoverable once the number of substrings containing at least one '*' reaches or exceeds some threshold m. Find the minimum time t at which this happens. If it's already irrecoverable before any attack, return 1. Walk through your algorithm and give time and space complexity.

“My first instinct was to just simulate it naively, count all substrings after each replacement, and check against m.”

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Amazon·Software Engineer·Online Assessment (OA)

May 2026

Did an Amazon SDE online assessment with two questions. Coding went okay but not great, and now I'm just sitting here wondering if I passed.

Solve a coding problem (Question 1 of 2 in the OA).
Debug a piece of code (Question 2 of 2 in the OA).

“Passed 9 out of 15 test cases.”

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Amazon·Software Engineer·Onsite - System Design / Architecture

May 2026

Amazon system design round for a software engineer role. The whole session was basically one big question about designing a library management system, and they went deep on every layer of it.

Design the API and database schema for a library management system that supports borrowing, returning, reserving books, and managing members and late fees.
How do you prevent two members from borrowing the last available copy at the same time?
How does your design enforce a per-member borrowing limit, and how do you compute overdue fees?
Walk through how the reservation (hold) queue works, including what happens when a copy is returned.
How would you extend this design to support multiple library branches where members can borrow from one branch and return to another?
A member disputes a late fee, claiming they returned the book on time. How does your design support auditing and resolving that dispute?
The copy count shown in search results is slightly stale. Where does that staleness come from, and how do you keep the borrow path correct even when the displayed count is wrong?
How would you implement loan renewals, and how do you reject a renewal if another member already has a hold on that title?

“This was the main question and it ate up the whole session.”

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Amazon·Software Engineer·Technical Phone Screen

May 2026

Amazon SWE interview with a tricky dynamic programming problem that layered multiple constraints on top of each other. The kind of question where you think you understand it and then realize you missed half the requirements.

Given an array of daily stock prices, find the maximum profit you can make with at most two buy-sell transactions, where selling incurs a fee and there's a mandatory one-day cooldown after each sale. Solution must run in O(n) time with O(1) extra space.

“The cooldown I expected.”

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Amazon·Software Engineer·Online Assessment (OA)

May 2026

Amazon SWE coding round with a streaming median problem. The window constraint made it interesting since you can't just sort on every query.

Design a comment rating system that supports two operations: adding a comment with an integer rating, and querying the median rating across the most recent N comments. The solution must handle streaming data efficiently without re-sorting on every median query.

“The naive approach of just grabbing the last N elements and sorting them every time is obviously too slow given the constraints.”

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Amazon·Software Engineer·Online Assessment (OA)

May 2026

Amazon SWE online assessment, pretty much what you'd expect: a coding problem with a complexity follow-up tacked on at the end.

Given an array of integers and a target value, find the two indices whose elements sum to the target. Each input has exactly one solution and you can't reuse the same index twice. Also provide the time complexity of your solution.

“Classic two-sum.”

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Amazon·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Went through a behavioral loop for a Software Engineer role at Amazon. Pretty much every question was leadership principle territory, which I expected, but the sheer volume of them back to back was a lot. Left feeling okay but not great.

Why do you want to work at Amazon?
Tell me about a time you delivered a simple solution to a complex problem.
What is your biggest professional failure and what did you learn from it?
Describe a time you missed a deadline. What happened and how did you handle it?
Walk me through a project where you exceeded what was expected of you.
Give an example of a time you worked under a very tight deadline.
What project are you most proud of and why?

“Prepared something about scale and customer obsession but it came out sounding rehearsed.”

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Amazon·Software Engineer·Onsite - Behavioral / Leadership

May 2026

Behavioral round at Amazon for a software engineer role, pretty much one question that they stretched into a full conversation about conflict and collaboration.

Tell me about a time you had a conflict with a coworker, manager, or partner team. What was the disagreement about, how did you handle the conversation, how did you resolve it, and what did you take away from it?

“I had a story ready but it was a bit too tidy, looking back.”

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Amazon·Software Engineer·Onsite - Coding / Algorithms

May 2026

Amazon SWE coding round, got a graph problem that looked like the classic course scheduling thing. Pretty standard if you know your topological sort, but the cycle detection part is where I think they're actually separating candidates.

Given a number of courses and a list of prerequisite pairs, return a valid ordering in which all courses can be completed. If a cycle exists making this impossible, return an empty array.

“I knew Kahn's algorithm going in so I wasn't totally lost, but I second-guessed myself on the cycle detection part and spent way too long explaining it before writing any code.”

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Amazon·Software Engineer·Online Assessment (OA)

May 2026

Amazon SWE online assessment with a scheduling/optimization problem. Nothing behavioral, just code. The problem looks deceptively simple but the constraint about start-time ordering trips you up if you're not careful.

Given an array where each element represents the unload time (in minutes) for a truck, and a maximum allowed total turnaround time, find the minimum number of dock bays needed so all trucks are unloaded within that time limit. Trucks must start unloading in order, and a bay can immediately take the next truck once it finishes.

“My first instinct was greedy, assign each truck to whichever bay finishes earliest.”

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