Moderate Stack Question 94 of 224

How do you compute the next greater temperature day for each index?

DSA interview set · Speak this in 60–90 seconds · Faridabad & Delhi NCR

Without indexScan every row

With indexJump to keys

CostWrites slower

Scan left to right and keep a stack of indices with decreasing temperatures

Why interviewers care about Stack:

This is a process

question about Stack.

Panels listen for order,

trade-offs, and what you would actually do on a DSA project - not buzzwords.

Stay structured

Name the idea, why it exists, then one short example.

Close cleanly

End with when you use it and one common pitfall.

Before you speak the answer, walk the interviewer through these steps:

1
Scan left to right
and keep a stack of indices with decreasing temperatures
2
when a warmer day
arrives, pop and set the difference in days.
3
Each index is pushed
and popped at most once: O(n) time and O(n) space.
4
Give an example
Nested scans would be O(n^2).
5
Common mistake
What juniors usually get wrong.
6
Close
When you pick this over the alternative.

Here's a short line you can speak, broken into clear beats:

Say this line

“Each index is pushed and popped at most once: O(n) time and O(n) space.”

Break into beats

Eachindexispushedandpopped

Speaking order

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Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.

Scan left to right and keep a stack of indices with decreasing temperatures when a warmer day arrives, pop and set the difference in days.