575. Distribute Candies

Posted 2022-08-03 wx62ea2466cca9a

Given an integer array with even length, where different numbers in this array represent different kinds of candies. Each number means one candy of the corresponding kind. You need to distribute these candies equally in number to brother and sister. Return the maximum number of kinds of candies the sister could gain.

Example 1:

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

Example 2:

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

Note:

The length of the given array is in range [2, 10,000], and will be even.
The number in given array is in range [-100,000, 100,000].

题目的意思是把一堆数字平均分成两堆，其中的一堆的最大的种类个数为多少。
HashMap统计每个数字出现的次数，然后统计就行，如果种类的数目多于总数字的半数，那么只能选半数的，否则不能平均分成两堆，否则就可以选择种类的个数做最多的分类个数。

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