How do you simulate asteroid collisions?
PICTURE THIS: STACK VS QUEUE
Simple meaning
Iterate asteroids and use a stack of survivors.
WHY — Stack instead of guessing?
Why interviewers care about Stack:
question about Stack.
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:
- 1Iterate asteroids and use
a stack of survivors.
- 2A positive then a
negative may collide: pop while the top is smaller and right-moving, explode both if equal, or discard the new one if the top is larger.
- 3Each asteroid is pushed/popped
O(1) amortized, so O(n) time and O(n) space.
- 4Give an example
One tiny concrete case you can say aloud.
- 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
Iterate asteroids and use a stack of survivors. A positive then a negative may collide: pop while the top is smaller and right-moving, explode both if equal, or discard the new one if the top is larger.