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Vector Similarity From Scratch
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Vector Similarity From Scratch

MediumPython

Problem

Implement a vector similarity function from scratch, focusing on computational efficiency.

Use cosine similarity for two dense numeric vectors. Implement vector_similarity(a, b), returning a float in [-1.0, 1.0]; return 0.0 if either vector has zero magnitude. Inputs have equal nonzero lengths, and you may use standard-library arithmetic but no numerical or machine-learning libraries.

Constraints

  • 1 <= len(a) = len(b) <= 100000
  • Each vector element is a finite integer or floating-point value
  • At least one vector may be all zeros
  • Do not use NumPy, SciPy, scikit-learn, or other numerical libraries

Function Signature

def vector_similarity(a, b):
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