1.  public String largestNumber(int[] nums) {
    2.         String[] strs = new String[nums.length];
    3.         for (int i = 0; i < nums.length; i++) {
    4.             strs[i] = String.valueOf(nums[i]);
    5.         }
    6.         Arrays.sort(strs, (o1, o2) -> {
    7.             return (o2 + o1).compareTo(o1 + o2);
    8.         });
    9.         StringBuilder builder = new StringBuilder();
    10.         for (String str : strs) {
    11.             builder.append(str);
    12.         }
    13.         String ans = builder.toString();
    14.         char[] str = ans.toCharArray();
    15.         int index = -1;
    16.         for (int i = 0; i < str.length; i++) {
    17.             if (str[i] != '0') {
    18.                 index = i;
    19.                 break;
    20.             }
    21.         }
    22.         return index == -1 ? "0" : ans.substring(index);
    23.     }