Learning New Algorithms and Data Structures

How do you approach learning new algorithms or data structures?

For the hands-on portion, implement a function that turns prerequisite relationships into a valid learning order. Return every topic once, after all of its prerequisites, or return an empty list when the prerequisites contain a cycle.

Input: a list of topic names and pairs [topic, prerequisite].

Output: a list of topic names in valid learning order, or [] if no such order exists.