1338. Reduce Array Size to The Half.cpp

class Solution {
public:
    int minSetSize(vector<int>& arr) {
        unordered_map<int, int> counter;
        priority_queue<int> q;
        int ans = 0, removed = 0;
        
        for (auto a : arr) counter[a]++;
        for (auto c : counter) q.push(c.second);
        
        while (removed < (arr.size() / 2)) {
            removed += q.top();
            q.pop();
            ++ans;
        }
        
        return ans;
    }
};