Which of the following approaches guarantees an optimal solution with efficient time complexity?
easy🔍 Pattern Recognition Q11 of Q15
Intervals - Meeting Rooms II (Minimum Conference Rooms)
You are given a list of meeting time intervals consisting of start and end times. Your task is to find the minimum number of conference rooms required so that all meetings can be held without overlap. Which of the following approaches guarantees an optimal solution with efficient time complexity?
ASort intervals by start time and use a min-heap to track the earliest ending meeting to reuse rooms efficiently.
BUse a brute force approach checking every pair of intervals for overlap and counting maximum overlaps.
CUse dynamic programming to find the maximum number of non-overlapping intervals and subtract from total intervals.
DSort intervals by end time and greedily assign rooms without tracking ongoing meetings.
Step-by-Step Solution
Step 1: Understand the problem requires tracking overlapping intervals to find minimum rooms.
Brute force checks all pairs but is inefficient; greedy by end time alone doesn't track concurrent overlaps.
Step 2: Recognize that sorting by start time and using a min-heap to track earliest ending meeting allows reusing rooms optimally.
This approach efficiently manages room allocation by freeing rooms as meetings end.
Final Answer:
Option A -> Option A
Quick Check:
Min-heap approach is standard optimal solution for this problem [OK]
Quick Trick:Min-heap tracks earliest end to reuse rooms efficiently [OK]
Common Mistakes:
MISTAKES
Assuming greedy by end time alone suffices
Thinking brute force is efficient enough
Confusing DP for interval scheduling with room allocation
Trap Explanation:
PITFALL
Greedy by end time works for max non-overlapping intervals but not for counting concurrent overlaps, making it look plausible but incorrect.
Interviewer Note:
CONTEXT
Tests if candidate can identify the correct pattern and optimal approach under pressure.
Master "Meeting Rooms II (Minimum Conference Rooms)" in Intervals
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