Distribute Candies问题及解法

问题描述：

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.

示例：

Input: candies = [1,1,2,2,3,3]Output: 3Explanation: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. 

Input: candies = [1,1,2,3]Output: 2Explanation: 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. 

问题分析：

本题主要是比较糖果种类的数目和总数目一半的大小。

过程详见代码：

class Solution {public:    int distributeCandies(vector<int>& candies) {        int res = 0;        int len = candies.size();        map<int,int> m;        for(int i = 0; i < len; i++)        {        if(m.count(candies[i]) == 0)         {        m.insert(pair<int,int>(candies[i],1));        res++;}}return min(res,(len / 2));    }};