18.leetCode575: Distribute Candies

题目：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:
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].

题意：给定一个偶数长度的整数数组，不同的数字表示不同的类别。将所有的糖果平分给弟弟和妹妹，问妹妹能拿到的糖果种类最多为多少？

思路：用一个map来统计出糖果的种类，如果糖果种类m大于每个人拥有的糖果数n，则返回m,否则返回n。

代码：

class Solution {    public static int distributeCandies(int[] candies) {            Map<Integer,Integer> map = new HashMap<Integer,Integer>();            for(int candy: candies){                if(map.containsKey(candy)){                    int value = map.get(candy)+1;                    map.put(candy,value);                }else                    map.put(candy,1);                }            int kind = map.size();            int num = (int)(candies.length/2);            if(kind > num)                return num;            else                return kind;        }}

注意：修改map中value的方法就是，重新将在map中put一个与原数据key相同但value不同的值。