Meeting Planner

You are given the availability of several employees as a list of time intervals during the day. Each employee’s availability is represented as an array of pairs of integers, where each pair [start, end] represents a block of time (in minutes from 0 to 1440) during which the employee is free. Note that the intervals for a single employee do not overlap.

Your task is to write a function that, given these availabilities and a required meeting duration (in minutes), returns the list of intervals (as pairs) during which all employees are available for a meeting that lasts at least the given duration.

For example, suppose the input is something like:

• Employee A: [[60, 120], [150, 210]]
• Employee B: [[90, 180]]
• Required meeting duration: 30 minutes

Your function should compute the intersection of these intervals and filter out any interval shorter than the required duration, returning all valid meeting slots.

Considerations:

• All time intervals are in minutes from the beginning of the day (0 minutes) to the end (1440 minutes).
• The function should handle cases where there might be no available slot long enough for the meeting.
• You can assume that the input lists are sorted by the start time for each employee.

Write a solution that efficiently computes the common availability intervals and adheres to clean code practices.