Valid Palindrome - Easy Python Two Pointers Interview Problem

Given a string s, return True if it is a palindrome, and False otherwise.

A string is a palindrome if, after converting all uppercase letters to lowercase and removing all non-alphanumeric characters, it reads the same forwards and backwards.

Example 1

Input: s = "A man, a plan, a canal: Panama"
Output: True
Explanation: After cleaning, "amanaplanacanalpanama" reads the same forwards and backwards.

Example 2

Input: s = "race a car"
Output: False
Explanation: After cleaning, "raceacar" is not a palindrome.

Example 3

Input: s = " "
Output: True
Explanation: After removing the space, the empty string is trivially a palindrome.

Constraints

1 <= s.length <= 2 * 10^5
s consists only of printable ASCII characters.

Hints