Understanding and have a natural feel for runtime complexity is very important when programming. It is very easy to implement a solution without thinking about complexity that will work fine for smaller data sets. As the dataset grows however, the program will take forever to compute. As you learn functional programming we should definitely spend a lecture on complexity.
Before this lecture
Before this lecture you should repeat what you've learned about asymptotic time complexity in the course in "Algorithms and Data Structures". The concepts that we will talk about during the lecture should not be new to you. We will only set them in perspective and exemplify with practical examples
These are the concepts that you should be comfortable to work with: