Given a string s, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. 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. Constraints: 1 <= s.length <= 2 * 105 s consists only of printable ASCII characters.