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Build a Vector Index From Scratch
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Build a Vector Index From Scratch

HardPython

Problem

Implement a custom vector similarity search index structure from scratch using basic math libraries.

Build a sign-based locality-sensitive hashing index from supplied hyperplanes, then rerank candidates by cosine similarity. Implement vector_similarity_search(vectors, queries, hyperplanes, k, max_hamming_distance) and return one list of vector indices per query, ordered by descending similarity and then ascending index. Use only Python's standard library.

Constraints

  • 1 <= len(vectors) <= 10^5
  • 1 <= len(queries) <= 10^3
  • 1 <= len(vectors[i]) == len(queries[j]) <= 256
  • 1 <= len(hyperplanes) <= 20
  • Every hyperplane has the same dimension as the vectors
  • 1 <= k <= len(vectors)
  • 0 <= max_hamming_distance <= 2
  • Vectors and queries contain finite real numbers
  • A query may return fewer than k results if its probed buckets contain fewer than k candidates
  • Zero vectors and zero queries are valid and have cosine similarity 0

Function Signature

def vector_similarity_search(vectors, queries, hyperplanes, k, max_hamming_distance):
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