Which modification to the algorithm is necessary to correctly determine if a person can attend all meetings without overlap?
hard🎤 Interviewer Follow-up Q15 of Q15
Intervals - Meeting Rooms I
Suppose the meeting intervals can be reused multiple times (i.e., a meeting can be attended multiple times if no overlaps occur). Which modification to the algorithm is necessary to correctly determine if a person can attend all meetings without overlap?
ASort intervals by end time and greedily select intervals to maximize non-overlapping meetings.
BNo change needed; the original algorithm already handles reuse correctly.
CUse a frequency map to count how many times each interval appears and check overlaps accordingly.
DSort intervals by start time and check overlaps as before, but also track counts of repeated intervals.
Step-by-Step Solution
Step 1: Understand reuse scenario
Reusing intervals means attending multiple instances of the same meeting, so we want to maximize the number of non-overlapping meetings.
Step 2: Identify correct approach
Sorting by end time and greedily selecting earliest finishing meetings maximizes non-overlapping intervals, handling reuse correctly.
Step 3: Why other options fail
Original algorithm only checks if all intervals can be attended once; frequency maps or tracking counts do not solve scheduling conflicts optimally.
Final Answer:
Option A -> Option A
Quick Check:
Greedy by end time is classic interval scheduling for maximum non-overlapping intervals [OK]
Quick Trick:Reuse requires interval scheduling by end time [OK]
Common Mistakes:
MISTAKES
Assuming original overlap check suffices for reuse
Trying to track counts without scheduling logic
Trap Explanation:
PITFALL
Candidates often think reuse means no algorithm change, but it requires maximizing intervals, not just overlap detection.
Interviewer Note:
CONTEXT
Tests understanding of problem variants and when to switch from overlap detection to interval scheduling.
Master "Meeting Rooms I" in Intervals
3 interactive learning modes - each teaches the same concept differently
