Valid Palindrome

📜 Problem Statement: A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.

Given a string s, return true if it is a palindrome, or false otherwise.

Examples

🔹 Example 1:

Input:

s = "A man, a plan, a canal: Panama"

Output:

true

Explanation: "amanaplanacanalpanama" is a palindrome.

🔹 Example 2:

Input:

s = "race a car"

Output:

false

Explanation: "raceacar" is not a palindrome.

🔹 Example 3:

Input:

s = " "

Output:

true

Explanation: s is an empty string "" after removing non-alphanumeric characters. Since an empty string reads the same forward and backward, it is a palindrome.

📝 Constraints:

• 1 <= s.length <= 2 * 10^5

• s consists only of printable ASCII characters.