Merge Intervals

Given an array of intervals where intervals[i] = [start_i, end_i], return the minimum number of intervals you need to remove to make the rest non-overlapping.

You are given two arrays of pairwise-disjoint, sorted-by-start intervals firstList and secondList. Return the intersection of the two interval lists — the list of intervals that overlap in both.

You are given the working schedules of several employees as a list schedule, where schedule[i] is a list of non-overlapping intervals (sorted by start time) representing employee i's working hours. Return the list of finite, positive-length intervals during which every employee is simultaneously free, sorted in ascending order.