Amazon Interview Questions — Page 155

Amazon·Software Engineer·Technical Phone Screen

Jul 2026

Amazon SWE interview, technical phone screen or take-home style question focused on shell scripting. One question, pretty practical, but there's more to it than it looks at first glance.

Write a shell script called script.sh that takes a username and a file path as arguments, then prints a single line in the format: <timestamp> <license> <user@hostname>. The username and hostname should be used to build the user@hostname part, the license value should be parsed from the given file, and the script should handle missing arguments, nonexistent files, and permission errors.

“I thought this was going to be a five-minute thing and then I got stuck on the timestamp format because nobody told me what format to use.”

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Amazon·Software Engineer·Onsite - Coding / Algorithms

Jul 2026

Amazon SWE coding round, one main problem about making change with minimum pieces plus two follow-ups. Pretty classic greedy territory but the follow-ups pushed it further than I expected.

You're implementing the change-dispensing logic for a self-checkout register. Given a dollar amount (up to two decimal places), return the minimum number of physical pieces (bills and coins) needed to make exact change, along with a per-denomination breakdown. Available denominations are $20, $10, $5, $1, $0.25, $0.10, $0.05, and $0.01.
How would you modify your loop to exit early once the remaining amount hits zero, instead of continuing to iterate through all denominations?
The register has a limited stock of each denomination. How do you modify your solution to respect those inventory limits, and what do you return if exact change can't be made?

“Greedy works here because the denominations are structured nicely.”

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Amazon·Software Engineer·Technical Phone Screen

Jul 2026

Amazon SWE interview with a tree problem that looks straightforward until you realize you need to track heights carefully through recursion. One question, but it had enough edge cases to keep me busy.

Given the root of a binary tree and an integer k, find the size (node count) of the k-th largest perfect binary subtree. A perfect binary tree has all internal nodes with two children and all leaves at the same depth. Collect the sizes of every perfect subtree in the tree into a sorted list and return the k-th largest, or -1 if fewer than k such subtrees exist.

“My first instinct was to just do a DFS and check each subtree independently, which would have been O(n^2) and I knew that was wrong but I said it out loud anyway.”

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Amazon·Data Scientist·Technical Phone Screen

Jul 2026

Amazon data scientist interview that was heavier on SQL internals than I expected. Most of the session was about cross-database compatibility and query semantics, the kind of stuff you think you know until someone asks you to explain it out loud.

A MySQL query using a column alias inside HAVING works fine, but the same query breaks on MS SQL Server. Why does this happen, and how would you rewrite it to work on both databases?
What does SELECT * FROM A B; do, and why is it valid SQL?
Among ORDER BY id, ORDER BY id ASC, and ORDER BY id DESC, which produces a different result from the other two and why?
Write the correct skeleton for a query that defines two CTEs and then selects from both of them.
For a column containing only uppercase letters, will these three predicates return identical rows: col IN ('A','B','C'), col BETWEEN 'A' AND 'C', and col >= 'A' AND col <= 'C'? Justify your answer.

“This one stung a little because I actually use MySQL day to day and never thought about why the alias worked.”

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Amazon·Data Scientist·Technical Phone Screen

Jul 2026

Amazon data scientist interview that was basically a deep dive into a single gnarly fraud modeling scenario. One question, four parts, and an hour to convince them you actually know what you're doing with imbalanced data in production. Felt more like a take-home crammed into a live session.

You've inherited a fraud detection model with severe class imbalance (positives around 2%) and weak validation performance. How would you diagnose whether it's underfitting or overfitting, propose three interventions you could ship in a single day, design a threshold selection procedure based on a specific cost structure, and define the minimum monitoring you'd put in place at deployment?

“This was a lot to hold in your head at once.”

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Amazon·Software Engineer·Technical Phone Screen

Jul 2026

Amazon BI Engineer interview with a SQL-heavy question on customer order behavior. Nothing too crazy but the window function angle required some actual thought.

Given an orders table with order ID, date, category, and customer ID, write a query that computes: (1) for each day and product category, what fraction of orders placed that day are the customer's first-ever order in that category, and (2) for each day, what fraction of all orders are a customer's first order across any category.

“Two-part question and I fumbled the second part at first.”

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Amazon·Software Engineer·Onsite - Behavioral / Leadership

Jul 2026

Amazon SWE behavioral loop, heavy on follow-ups. They really want to dig into your specific contributions, the numbers behind your decisions, and what you actually learned. Not a vibe check, more like a deposition.

Tell me about a time you initially failed at something but eventually turned it into a success.
Describe a conflict you had with a teammate or stakeholder. How did you handle it?
Walk me through a time you improved an important metric. What was the metric, what did you do, and what was the measurable outcome?
Tell me about a time using generative AI in your work went wrong. What broke, how did you figure it out, and what did you put in place afterward?

“The follow-ups are where this gets uncomfortable.”

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Amazon·Software Engineer·Technical Phone Screen

Jul 2026

Amazon SWE interview with a grid traversal problem. Pretty standard coding round, nothing too surprising, but it's the kind of question where you either know your DFS/BFS cold or you fumble the edge cases.

Given a 2D grid of 0s and 1s, find the largest connected region of 1s using 4-directional movement and return its area.

“Went with DFS and it worked fine.”

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Amazon·Software Engineer·Onsite - Behavioral / Leadership

Jul 2026

Behavioral round at Amazon for a software engineering internship. Three questions, all centered on how you handle complexity and failure. Nothing too surprising but the failure question tripped me up more than I expected.

Tell me about the most complex project you've worked on. How did you weigh the different options available to you?
Describe a project that went badly or failed. What happened and what did you take away from it?
What would you do if you realized mid-project that your current approach wasn't the right one?

“I rambled.”

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Amazon·Software Engineer·Technical Phone Screen

Jul 2026

Amazon BI Engineer interview with a SQL problem that looks straightforward but has a subtle twist if you haven't thought about unordered pairs before.

Given a flights table with departure and arrival city columns, write a SQL query that returns all unique city pairs treating (A, B) and (B, A) as the same route.

“I knew roughly what they wanted but blanked on the exact syntax for LEAST/GREATEST for a second.”

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