content: package codingquestions.leetcode;
  
  /*
   * 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.
   
   */
  public class IsPallindrome {
      public static void main(String[] args) {
          IsPallindrome.isPalindrome("A man, a plan, a canal: Panama");
      }
  
      public static boolean isPalindrome(String s) {
          s = s.replaceAll("[^A-Za-z0-9]", "");
          StringBuffer sb = new StringBuffer(s);
          sb.reverse();
          return s.equalsIgnoreCase(sb.toString());
  
      }
  }
  