How do you find the largest element in an unsorted array?
PICTURE THIS: ARRAY IN MEMORY
Index starts at 0. Scan once for max — O(n).
Simple meaning
Scan once while keeping a running maximum, initializing it to the first element or negative infinity.
WHY — Arrays instead of guessing?
Why interviewers care about Arrays:
question about Arrays.
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:
- 1Scan once while keeping
a running maximum, initializing it to the first element or negative infinity.
- 2That is a single
O(n) pass with O(1) extra space, which is optimal because every element must be inspected.
- 3Sorting first would be
O(n log n) and is unnecessary if you only need the max.
- 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
Scan once while keeping a running maximum, initializing it to the first element or negative infinity. That is a single O(n) pass with O(1) extra space, which is optimal because every element must be inspected.