Was asked the following question during my onsite. Ran out of time before forming a full solution, still not sure what a good approach to this would be.

Given on-call rotation schedule for multiple people by: their name, start time and end time of the rotation:

Abby 1 10
Ben 5 7
Carla 6 12
David 15 17

Your goal is to return rotation table without overlapping periods representing who is on call during that time. Return "Start time", "End time" and list of on-call people:

1 5 Abby
5 6 Abby, Ben
6 7 Abby, Ben, Carla
7 10 Abby, Carla
10 12 Carla
15 17 David