Why interviewers ask this
A classic problem that tests basic logic and edge-case thinking.
How to approach it
Explain normalization of case and spaces, then compare characters from both ends, and state time complexity.
Example answer
I would lowercase the string, remove non-alphanumeric characters, and use two pointers from the start and end moving inward. It runs in linear time with constant extra space.
What a weak answer sounds like
I would write a loop and compare each letter.
It is vague, has no example and gives the interviewer nothing to remember.
Common mistake
Ignoring empty strings or case differences.
Follow-up questions to expect
- What is the time complexity?
- How do you handle spaces and punctuation?
- Can you do it without extra memory?
How to practise
Solve it in your language of choice and list five test cases including empty and single-character strings.
Use this as a pattern, not a script. Answer in your own words with your own examples.
Note: This is general information, not professional advice, and it cannot guarantee any job, admission, salary or result. Check official sources for current rules and dates.