In our last post, we covered data structures, or the ways that programming languages store data in memory. We touched upon abstract data types, theoretical entities that are implemented via data structures. The concept of a “vehicle” can be viewed as an abstract data type, for example, with a “bike” being the data structure.

Imagine you build a wildly popular app that is quickly growing towards a million users. (Congrats!) While users love the app, they’re complaining that the app is becoming slower and slower, to the point that some users are starting to leave. You notice that the main bottleneck is how user info is retrieved during authentication: currently, your app searches through an unsorted list of Python dictionaries until it finds the requested user ID.