Easy Arrays Question 6 of 224

How do you rotate an array to the right by k steps in place?

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

01234

Index starts at 0. Scan once for max — O(n).

Reduce k modulo n, reverse the whole array, reverse the first k elements, then reverse the rest.

Why interviewers care about Arrays:

This is a process

question about Arrays.

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
Reduce k modulo n,
reverse the whole array, reverse the first k elements, then reverse the rest.
2
Three reverses are O(n)
time and O(1) space.
3
A extra-array rotation is
simpler to explain but uses O(n) space, so lead with the reverse trick in interviews.
4
Give an example
One tiny concrete case you can say aloud.
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

“Three reverses are O(n) time and O(1) space.”

Break into beats

ThreereversesareOntime

Speaking order

2987408337471632900

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

Reduce k modulo n, reverse the whole array, reverse the first k elements, then reverse the rest. Three reverses are O(n) time and O(1) space.