These are Algorithms questions of the kind Amazon actually asks — the patterns reported from Amazon's AI-engineering rounds, where design trade-offs, scale and failure modes matter as much as definitions. Treat this page as a mock interview: say every answer out loud before revealing it. If one surprises you, the lesson behind it is linked at the bottom.
Amazon Algorithms concept questions
Rotten oranges: a grid holds fresh oranges, rotten oranges, and empty cells. Every minute, fresh oranges adjacent to rotten ones rot. How many minutes until all rot (or −1)? Why is this BFS, and what's special about the start?
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Amazon Algorithms applied & hands-on questions
Merge [[1,3],[2,6],[8,10],[15,18]] into non-overlapping intervals. What must happen before any merging can work?
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Find the maximum subarray sum of [-2, 1, -3, 4, -1, 2, 1, -5, 4] in O(n), tracing both running values.
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How to use this page: Amazon rarely asks something you've never seen — they ask a standard Algorithms concept and then push one level deeper ("why?", "what would you do if..."). Master the concept in the Algorithms course lessons, and the follow-up stops being scary.
Keep practising: Binary Search, Dynamic Programming, BFS & DFS and Patterns & Strategy cover what most Amazon Algorithms rounds test.