The Expand-Around-Center Strategy: Cracking LeetCode's Palindrome Challenge

Longest palindromic substring is a must-know problem in technical interview preparation and competitive programming, directly testing string manipulation skills and algorithmic thinking. This guide introduces the elegant expand-around-center approach, which achieves O(N²) time complexity—a significant improvement over naive O(N³) solutions. Mastering this technique not only prepares you for LeetCode interviews but also equips you with a powerful strategy applicable to many similar algorithmic challenges.