Method compare

LargestNumber.java:10–14

(String a, String b)

        // KNlogN
        Arrays.sort(elements, new Comparator<String>(){
            public int compare(String a, String b){
                String first = a + b;
                String sec = b + a;
                return sec.compareTo(first); //K
            }
        });
        if(elements[0].equals("0")){
            return "0";