Find Longest Palindromic Substring

Given a string, find the longest substring that is a palindrome. A palindrome is a sequence of characters that reads the same forwards and backwards.

Your task is to implement the findLongestPalindrome method that takes a string as input and returns the longest palindromic substring.

Requirements

If there are multiple palindromic substrings of the same maximum length, return the first one found (leftmost)
Return null for null input
Return empty string for empty string input
The comparison should be case-sensitive
Single characters are considered palindromes

Example 1:

String input = 'babad';
String result = findLongestPalindrome(input);
// Returns: 'bab' (or 'aba' - both are valid, but 'bab' appears first)

Example 2:

String input = 'cbbd';
String result = findLongestPalindrome(input);
// Returns: 'bb'

Example 3:

String input = 'racecar';
String result = findLongestPalindrome(input);
// Returns: 'racecar' (entire string is a palindrome)

Example 4:

String input = 'a';
String result = findLongestPalindrome(input);
// Returns: 'a' (single character is a palindrome)

Example 5:

String input = null;
String result = findLongestPalindrome(input);
// Returns: null

Example 6:

String input = '';
String result = findLongestPalindrome(input);
// Returns: ''

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