125. Valid Palindrome
Character.isLetterOrDigit()
1 class Solution { 2 public boolean isPalindrome(String s) { 3 if(s.length() == 0) return true; 4 StringBuilder sb = new StringBuilder(); 5 for(int i = 0; i < s.length(); i++){ 6 if(Character.isLetterOrDigit(s.charAt(i))){ 7 sb.append(s.charAt(i)); 8 } 9 } 10 String str = sb.toString().toLowerCase(); 11 sb = new StringBuilder(str); 12 StringBuilder sb1 = new StringBuilder(str); 13 sb.reverse(); 14 15 return sb.toString().equals(sb1.toString()); 16 17 } 18 }