DSA TrainerMeeting Rooms II
Given an array of meeting time intervals, return the minimum number of conference rooms required to hold all meetings.
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Problem
Given an array of meeting time intervals intervals where intervals[i] = [starti, endi], return the minimum number of conference rooms required.
Input
An array of intervals `intervals` where `intervals[i] = [start, end]`.
Output
The minimum number of conference rooms required.
Examples
Input: intervals = [[0,30],[5,10],[15,20]]
Output: 2
Room 1: [0,30]. Room 2: [5,10], then [15,20] (reuses the room).
Input: intervals = [[7,10],[2,4]]
Output: 1
One room handles both (no overlap).
The brute-force approach
Try all orderings of meetings and simulate room assignment. Track the minimum rooms needed across all valid orderings.
# Too complex to enumerate — simulate directly instead.Exponential — combinatorial.
Spotting the pattern
This is a Greedy problem. The key question to ask yourself:
Why does the min-heap always give you the room most likely to be free? What would you miss if you checked a random occupied room instead?
Answering that is where it clicks, and it's exactly what the guided walkthrough below builds with you: the pattern reasoning, a progressive hint ladder that never spoils the answer, a row-by-row dry run, the optimized solution, and an in-browser editor to run your code against real test cases.
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