Given an array of meeting time intervals intervals where intervals[i] = [starti, endi], return the minimum number of conference rooms required.
Examples
Example 1
Input: intervals = [[0,30],[5,10],[15,20]]
Output: 2
We need two rooms: one for [0,30] and one for [5,10] (or [15,20]).
Example 2
Input: intervals = [[7,10],[2,4]]
Output: 1
The two meetings do not overlap, so we only need one room.
Constraints
1 <= intervals.length <= 10^40 <= starti < endi <= 10^6