Distribute Candies

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 candies.

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 candies.

Note:

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

分析：数字编号的不同代表糖果种类的不同，将一堆糖果平均分给俩兄妹，妹妹的种类要最多。

思路：只存在两种情况：种类数大于等于总数的一半时，妹妹会有一半种类数的糖果;种类数小于总数的一半时，妹妹会拿到所有种类数的糖果。

JAVA CODE

class Solution {
    public int distributeCandies(int[] candies) {
        // 需要将整型数组转成interger,因为基本类型不能直接转成set。
        Integer[] cc = new Integer[candies.length];
        for (int i = 0; i < cc.length; i++)
            cc[i] = new Integer(candies[i]);
        return Math.min(new HashSet<Integer>(Arrays.asList(cc)).size(), candies.length/2);
    }
}