How do you determine if a sentence is a palindrome ignoring punctuation?
This question asks for a string cleaning and comparison algorithm. It tests string manipulation and normalization techniques.
Why Interviewers Ask This
Interviewers ask this to evaluate a candidate's ability to preprocess data before applying logic. It tests attention to detail regarding character filtering and case sensitivity. The question also checks if the candidate can combine multiple string operations efficiently.
How to Answer This Question
Explain normalizing the string by removing non-alphanumeric characters and converting to lowercase. Then use a two-pointer approach to compare characters from the start and end moving inward. Stop when pointers meet. Discuss time and space complexity considerations.
Key Points to Cover
- String normalization
- Filtering characters
- Case insensitivity
- Two-pointer comparison
Sample Answer
First, I normalize the input string by removing spaces, dots, and other non-alphanumeric characters, and convert everything to lowercase. Then, I use a two-pointer technique starting from both ends of the cleaned string.…
Common Mistakes to Avoid
- Ignoring case sensitivity
- Failing to remove all punctuation
- Using extra string copies inefficiently
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