575. Distribute Candies*

https://leetcode.com/problems/distribute-candies/

题目描述

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.

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].

C++ 实现 1

这道题解决重点在理清题意. 首先, 数组中的数字表示的是 candy 的类别, 而不是颗数. 为了解决这倒题, 需要先统计有多少个类别, 由于女孩只能拿一半个数的 candy, 为了能拿到更多的类别, 她可以每种类别挑一颗糖. 如果说一半个数, 假设为 count, 小于或等于总的类别数, 那么女孩最多拿到 count 个类别的糖; 否则, 女孩可以拿到所有类别的糖.

class Solution {public:int distributeCandies(vector<int>& candies) {int res = 0, count = candies.size() / 2;unordered_set<int> record(candies.begin(), candies.end());return count <= record.size() ? count : record.size();}
};