When a Loop Inside a Loop Is Too Slow: Hash Tables at Work

Turn the gym's slow year-end reports into one pass: count each member's visits, find the first member to come back, and stop asking a slow server the same question twice. Then choose a list, a set or a dictionary for a job, and say why.

Updated

Cheat sheet: When a Loop Inside a Loop Is Too Slow: Hash Tables at Work
Category
Data Structures
Level
Journeyman
Tags
Cache (software-development), Cache Hit, Cache Miss, data structures, Frequency Count