Given an integer array of `digits`

, return the largest multiple of **three** that can be formed by concatenating some of the given digits in any order.

Since the answer may not fit in an integer data type, return the answer as a string.

If there is no answer return an empty string.

**Example 1:**

Input:digits = [8,1,9]Output:"981"

**Example 2:**

Input:digits = [8,6,7,1,0]Output:"8760"

**Example 3:**

Input:digits = [1]Output:""

**Example 4:**

Input:digits = [0,0,0,0,0,0]Output:"0"

**Constraints:**

`1 <= digits.length <= 10^4`

`0 <= digits[i] <= 9`

- The returning answer must not contain unnecessary leading zeros.

class Solution {
public String largestMultipleOfThree(int[] digits) {
}
}