ITPEC FE Subject A April 2024 Question 15

Values computed from the data used as storage addresses — hashing applies a function to the key and stores the record at the resulting address.

A hash function converts a key into an address in a table. A search repeats the same calculation and goes straight to that address, so the search time stays about constant however many records are stored. Ideal hashing is the case with no collisions: every key maps to its own address.

Answer (b)

Why not others:

• •(a) — adding recognition and decision functions to interpret the intention of a search request describes an intelligent, agent-style search, not an addressing method
• •(c) — searching large accumulated data for trends, correlations and patterns is data mining
• •(d) — using lists of synonyms and equivalent words to raise the keyword hit ratio is thesaurus-based search

Key rule: Hashing turns a search into one calculation plus one access, address = h(key), and stays that fast only while collisions are rare.

Algorithm and Programming · AI-written, may contain errors