How do you erase the fewest intervals so the rest do not overlap?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
Sort by end time and keep an interval if it starts after or at the last kept end
WHY — Greedy instead of guessing?
Why interviewers care about Greedy:
question about Greedy.
trade-offs, and what you would actually do on a DSA project - not buzzwords.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Sort by end time
and keep an interval if it starts after or at the last kept end
- 2Why it exists
otherwise drop it.
- 3Sorting O(n log n),
scan O(n), space O(1) besides sort.
- 4Sorting by start and
using a heap is the meeting-rooms variant, not this one.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Sort by end time and keep an interval if it starts after or at the last kept end otherwise drop it.