import java.util.Arrays;

 import java.util.Comparator;

 class Solution {

     public String largestNumber(int[] num) {

         if(null==num||num.length<1)

             return "";

         String[] snum = new String[num.length];

         for(int i=0; i<num.length; i++)

             snum[i] = String.valueOf(num[i]);

         Comparator<String> cmp = new Comparator<String>(){

             @Override

             public int compare(String s1,String s2){

                 String c1 = s1+s2;

                 String c2 = s2+s1;

                 return c2.compareTo(c1);

             }

         };

         Arrays.sort(snum,cmp);

         if(snum[0].charAt(0)=='0')

             return "0";

         StringBuilder ans = new StringBuilder();

         for(String each:snum)

             ans.append(each);

         return ans.toString();

     }

 }