Given an array of meeting time intervals where intervals[i] = [startᵢ, endᵢ], return the minimum number of conference rooms required so that no two simultaneous meetings share a room.
A meeting that ends exactly when another begins does not require a second room — the room frees up in time.
[[0,30],[5,10],[15,20]][[7,10],[2,4]][[1,5],[8,9],[8,9]][][[2,7]][[1,10],[2,7],[3,19],[8,12],[10,20],[11,30]][[0,5],[5,10],[10,15]]