How do you solve product of array except self without division?
Reported in Atlassian interview loops. Array prefix-suffix pattern often asked in coding rounds.
Interview scenario
Context for Atlassian candidates:
Return an array where each index contains the product of all numbers except itself, without using division.
Model answer
Try answering aloud first
Cover trade-offs, structure, and a concrete example before revealing the baseline response.
How to frame this at Atlassian: Connect your answer to measurable impact, clarity of thought, and trade-offs the team cares about. Below is a strong baseline response you can adapt with your own project examples.
Build prefix products from left to right and suffix products from right to left. The result at index i is prefix up to i-1 multiplied by suffix from i+1.
You can optimize space by storing prefix directly in the output array and using one running suffix variable in a backward pass. Time remains O(n) and extra space is O(1) excluding output.
Discuss why division-based logic fails with zeros, while prefix-suffix handles one or multiple zeros naturally.
Discussion
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