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.

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 * 105
  • s consists only of printable ASCII characters.