public boolean isPalindrome1(String s) {
        if (s == null || s.length() == 0 || s.trim().length() == 0) {
            return true;
        }
        String newS = "";
        for (char c : s.toLowerCase().toCharArray()) {
            if (isCharNum(c)) {
                newS += c;
            }
        }
        for (int i = 0, j = newS.length() - 1; i < j; i++, j--) {
            if (newS.charAt(i) != newS.charAt(j)) {
                return false;
            }
        }
        return true;
    }