天池 在线编程 聪明的销售（计数+贪心）

ids 的大小不超过 10^5
1 <= ids[i] <= 1000000
1 <= m <= 100000


样例 1
输入：
[1,1,1,2,2,3]
2
输出：
2

class Solution {
public:
    /**
     * @param ids: ID number of items
     * @param m: The largest number of items that can be remove
     * @return: the result of the min item
     */
    int minItem(vector<int> &ids, int m) {
        // write your code here
        unordered_map<int,int> goods_count;
        for(auto i : ids)
            goods_count[i]++;
        vector<int> count;
        for(auto &gc : goods_count)
            count.push_back(gc.second);
        sort(count.begin(), count.end());
        int kinds = count.size(), i = 0;
        while(i < kinds && m > 0)
        {
            int take = min(m, count[i]);
            m -= take;
            count[i] -= take;
            if(count[i] == 0)
                i++;
        }
        return kinds-i;
    }
};