public String largestNumber(int[] nums) {
if (nums == null || nums.length == 0) {
String[] strs = new String[n];
for (int i = 0; i < n; i++) {
Arrays.sort(strs, (a, b)->((b + a).compareTo(a + b)));
if (strs[0].charAt(0) == '0') {
StringBuilder res = new StringBuilder();
for (String str : strs) {