```
public class Solution
extends Object
```
1815 - Maximum Number of Groups Getting Fresh Donuts\. Hard There is a donuts shop that bakes donuts in batches of `batchSize`. They have a rule where they must serve **all** of the donuts of a batch before serving any donuts of the next batch. You are given an integer `batchSize` and an integer array `groups`, where `groups[i]` denotes that there is a group of `groups[i]` customers that will visit the shop. Each customer will get exactly one donut. When a group visits the shop, all customers of the group must be served before serving any of the following groups. A group will be happy if they all get fresh donuts. That is, the first customer of the group does not receive a donut that was left over from the previous group. You can freely rearrange the ordering of the groups. Return _the **maximum** possible number of happy groups after rearranging the groups._ **Example 1:** **Input:** batchSize = 3, groups = [1,2,3,4,5,6] **Output:** 4 **Explanation:** You can arrange the groups as [6,2,4,5,1,3]. Then the 1^st, 2^nd, 4^th, and 6^th groups will be happy. **Example 2:** **Input:** batchSize = 4, groups = [1,3,2,5,2,2,1,6] **Output:** 4 **Constraints:** * `1 <= batchSize <= 9` * `1 <= groups.length <= 30` * 1 <= groups[i] <= 10⁹

public int maxHappyGroups(int batchSize,
                          int[] groups)

Class Solution