public boolean isPalindrome(String s) {
        if(s.length()==0||s==null){
            return true;
        }

        char[] x = s.toCharArray();
        int left = 0;
        int right = x.length-1;
        boolean check =true;

        while(left<right){
            if(!Character.isLetterOrDigit(x[left])){
                left++;
            }
            else if(!Character.isLetterOrDigit(x[right])){
                right--;
            }
            else{
                if(Character.toLowerCase(x[left]) != Character.toLowerCase(x[right])){
               check = false;

                 }
            left++;
            right--;
            }
        }
        return check;
    }