Detect palindrome in string
Last updated: October 10, 2025
Quick Overview
Given a string, write a function to determine if it is a palindrome, meaning it reads the same forwards and backwards. The function should return a boolean value: true if the string is a palindrome, and false otherwise. Consider only alphanumeric characters and ignore case sensitivity when making the determination.
Uber
October 10, 2025247
11
3,134 solved
Given a string, write a function to determine if it is a palindrome, meaning it reads the same forwards and backwards. The function should return a boolean value: true if the string is a palindrome, and false otherwise. Consider only alphanumeric characters and ignore case sensitivity when making the determination.
This coding problem is frequently asked during Onsite at Uber. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Uber expects candidates to write production-quality code, not just solve the puzzle.
What the Interviewer Expects
- Quickly identify the optimal approach and its theoretical basis
- Handle complex algorithm design with multiple interacting components
- Write concise, elegant code under time pressure
- Prove correctness of your approach and discuss alternative solutions
- Optimize beyond the obvious: discuss constant factor improvements
- Address follow-up variations and explain how the solution generalizes
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- What if the input doesn't fit in memory?
- How would you modify your solution to handle streaming input?
- What is the worst-case input for your solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
To determine if a string is a palindrome, we can utilize the two-pointer technique. This method is appropriate here because we need to simultaneously compare characters from both ends of the strin...
Approach
- Initialize two pointers: one at the start (
left) and one at the end (right) of the string. - While the
leftpointer is less than therightpointer: a. Increment theleftpointer if th...
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