Solution: Employee Free Time

Statement

You’re given a list containing the schedules of multiple employees. Each person’s schedule is a list of non-overlapping intervals in a sorted order. An interval is specified with the start and end time, both being positive integers. Your task is to find the list of finite intervals representing the free time for all the employees.

Constraints:

• $1 \leq$ schedule.length , schedule[i].length $\leq 50$

• $0 \leq$ interval.start < interval.end $\leq 10^8$, where interval is any interval in the list of schedules.