LeetCode 575. Distribute Candies

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575. Distribute Candies

一、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.

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].

二、输入输出

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.

三、解题思路

题目的意思是找到最多的不同的数字，这个个数不能超过总数字个数的一半。

把原字符存储到map中并记录下每个数字出现的个数。依次遍历这个map，如果个数为正，那么类型数就加1 总个数也加1 类型数不会超过map的size 总个数不能超过原数组长度的一半。这两个判断条件是关键。

class Solution {
public:int distributeCandies(vector<int>& candies) {map<int, int> dict;for (auto ite : candies){if(dict.find(ite) == dict.end()) dict.insert(make_pair(ite, 1));else dict[ite]++;}int ret = 0, count = 0, tot = candies.size(), totKind = dict.size();for (auto ite : dict){if(ite.second > 0) {ite.second--;ret++;count++;}if(ret >= totKind || count >= tot/2)break;}return ret;}
};