Longest Palindromic Substring

Problem

Return the longest contiguous palindrome; for ties, return the earliest.

Examples

Example 1

Input: "babad"

Output: "bab"

Example 2

Input: "cbbd"

Output: "bb"

Input and output use JSON-compatible values. For linked-list and tree questions, arrays represent the node structure as described above. Your code should implement solve(input).

Write your solutionImplement solve(input). Your draft is saved in this browser.

Compiler

How to solve Longest Palindromic Substring

One approach is: Expand around every possible middle point. The reference code demonstrates this method. Compare the example and edge-case tests, then consider time and space usage.

Time and space complexity

Discuss the dominant operations and any additional data structures used by your implementation.

Practise and improve

Choose JavaScript, TypeScript or Python, complete the starter code, then select Run Tests. Request a hint when you need guidance, or choose View solution and confirm if you would like to study the reference implementation.