Coding - Meeting Rooms II

Problem

You are building a scheduling system for a company that needs to allocate conference rooms efficiently. Given a collection of meeting time intervals where each interval is represented as [start, end], determine the minimum number of conference rooms required to accommodate all meetings without any scheduling conflicts.

Each meeting occupies a room from its start time (inclusive) to its end time (exclusive). For example, a meeting from [0, 30] means the room is occupied from time 0 up to (but not including) time 30.

Requirements

• Calculate the minimum number of rooms needed so that no two meetings overlap in the same room

• Handle empty input appropriately (return 0 for no meetings)

• Meetings with the same start and end times are considered overlapping

• A meeting ending at time T does not conflict with a meeting starting at time T

Constraints

• 0 ≤ meetings.length ≤ 10,000

• Each meeting interval is represented as [start, end] where 0 ≤ start < end ≤ 1,000,000

• Target time complexity: O(n log n) where n is the number of meetings

• Target space complexity: O(n)

Examples

Example 1:

` Input: [[0, 30], [5, 10], [15, 20]] Output: 2 Explanation:

• At time 0, meeting 1 starts (1 room in use)
• At time 5, meeting 2 starts (2 rooms in use)
• At time 10, meeting 2 ends (1 room in use)
• At time 15, meeting 3 starts (2 rooms in use)
• At time 20, meeting 3 ends (1 room in use)
• At time 30, meeting 1 ends (0 rooms in use) Maximum rooms needed: 2 `

Input: [[7, 10], [2, 4]] Output: 1 Explanation: The meetings don't overlap, so 1 room is sufficient.

Input: [[1, 10], [2, 6], [3, 5], [7, 9]] Output: 3 Explanation: At time 3, three meetings are happening simultaneously: [1,10], [2,6], and [3,5].