Greedy Algorithms - Minimum Platforms (Train Stations)
Consider the min-heap approach for minimum platforms. What is the output when arrivals = [1000] and departures = [1000] (a single train arriving and departing at the same time)?
Consider the min-heap approach for minimum platforms. What is the output when arrivals = [1000] and departures = [1000] (a single train arriving and departing at the same time)?
medium🧾 Code Trace Q4 of Q15
Step-by-Step Solution
Solution:
Step 1: Process single train arrival and departure
Heap is empty initially. Arrival=1000, no trains to pop. Push departure=1000. Heap size=1.Step 2: Max platforms updated to 1
Return max_platforms=1.Final Answer:
Option D -> Option DQuick Check:
Single train requires one platform [OK]
Quick Trick: Single train always needs one platform [OK]
Common Mistakes:
MISTAKES- Assuming 0 platforms if arrival=departure
- Confusing <= with < in heap pop condition
- Expecting error on equal times
Trap Explanation:
PITFALL- Candidates often think arrival == departure means no platform needed or causes error, but one platform is required.
Interviewer Note:
CONTEXT- Tests handling of edge cases with equal arrival and departure times.
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