What is a Bloom Filter?

What is a Bloom Filter?

Approach: Explain a space-efficient probabilistic test for set membership.

A probabilistic data structure that tests if an element is in a set. It can return 'possibly in set' or 'definitely not in set'. It never has false negatives but may have false positives.

Follow-up: How do you reduce the false positive rate?

Key concepts: hashing, false positives, no false negatives.