575 Distribute Candies 分发糖果问题

给定一个整数数组，这个数组的长度为偶数，不同的数字代表不同的种类糖果。每一个数字意味着一个糖果。你需要把这些糖果等量的分发给弟弟妹妹。返回的最大种类数量糖果妹妹可以获得。

example1

Input: candies = [1,1,2,2,3,3]
Output: 3
Explanation:
There are three different kinds of candies (1, 2 and 3), and two candies for each kind.
Optimal distribution: The sister has candies [1,2,3] and the brother has candies [1,2,3], too. 
The sister has three different kinds of candies. 

example2

Input: candies = [1,1,2,3]
Output: 2
Explanation: For example, the sister has candies [2,3] and the brother has candies [1,1]. 
The sister has two different kinds of candies, the brother has only one kind of candies. 

solution

public class Solution {
    public int distributeCandies(int[] candies) {
        HashSet < Integer > set = new HashSet < > ();
        for (int candy: candies) {
            set.add(candy);
        }
        return Math.min(set.size(), candies.length / 2);
    }
}

不同种类的数量大于一半，就得到一半的糖果数量，若小于一半，则为全部的种类量。