Analyze matrix multiplication complexity
Quick Overview
This question evaluates understanding of time and space complexity for matrix multiplication and memory accounting in ML workloads, testing competency in asymptotic analysis, linear algebra operations, and resource estimation.
OpenAI
Feb 11, 2026, 12:00 AM
Machine Learning Engineer
Technical Screen
Software Engineering Fundamentals
11
0
You are asked in an ML coding interview:
Given two dense matrices A and B, where A has shape (m, n) and B has shape (n, p), you compute C = A @ B (standard matrix multiplication, as in NumPy/PyTorch).
- What is the time complexity of this operation in Big-O notation (in terms of m, n, p)?
- What is the space complexity (extra memory usage) of this operation? Clearly state whether you count the output matrix C as part of the space.
Optional follow-up: How does your answer change (if at all) if A and B are batched, e.g., A is (b, m, n) and B is (b, n, p) and you compute a batched matmul?
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