InterviewDigestTechnical2026-08-16
Trapping Rain Water (with discussion on O(n) space and O(1) space approaches)
AI-Expanded — inferred from the question title, not from the original candidate report
Given an array of non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. Provide an implementation that achieves O(n) time complexity, and discuss the trade-offs between an O(n) space approach using auxiliary arrays or a stack versus an O(1) space approach using the two-pointer technique.
Context & Summary
Face-to-face interview (1 hour 30 mins) where the interviewer asked three technical questions and discussed OOPs concepts.
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