Find the longest palindromic substring
Company: Intersystems
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: easy
Interview Round: Technical Screen
## Problem
Given a string `s`, find the **longest contiguous substring** of `s` that is a palindrome (reads the same forward and backward).
### Input
- A string `s` consisting of ASCII letters/digits (you may assume standard printable characters).
### Output
Return **one** longest palindromic substring. If there are multiple valid answers with the same maximum length, return any of them.
### Constraints
- `1 <= |s| <= 2000`
### Examples
- Input: `"babad"` → Output: `"bab"` (or `"aba"`)
- Input: `"cbbd"` → Output: `"bb"`
### Notes
In the interview setting, you may be asked to **explain the approach verbally** (no code required), including time/space complexity and edge cases.
Overview: This question evaluates string manipulation and algorithmic problem-solving skills, focusing on identifying palindromic substrings and reasoning about performance and edge cases. Commonly asked in the Coding & Algorithms domain to assess practical algorithmic application, it gauges understanding of time/space complexity, input constraints, and robustness in implementation.
Read the full Intersystems Software Engineer interview experience this question came from