Why "Play Track 750,000" Is Instant and "Find Golden Hour" Isn't: Memory as Mailboxes

Find out why a music app plays track 750,000 in one step but has to search for a song by its title, and how a program keeps songs of different sizes without losing that one step.

Updated

Cheat sheet: Why "Play Track 750,000" Is Instant and "Find Golden Hour" Isn't: Memory as Mailboxes
Category
Data Structures
Level
Novice
Tags
Array (data-structures), data structures, Memory Address, Reference (software-development), software-development