UVa 11369 - Shopaholic

// UVa 11369 - Shopaholic
#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;

bool comp(int a, int b) {
	return a > b;
}

int main() {
	int cases;
	cin >> cases;
	for (; cases > 0; cases--) {
		int n;
		cin >> n;
		vector<int> v;
		for (int i = 0; i < n; i++) {
			int x;
			cin >> x;
			v.push_back(x);
		}
		sort(v.begin(), v.end(), comp);
		unsigned long long int sol = 0;
		for (int i = 2; i < n; i += 3) {
			sol += v[i];
		}
		cout << sol << endl;
	}
	return 0;
}