2+1 세일

www.acmicpc.net/problem/11508

11508번: 2+1 세일

#include<iostream>
#include<vector>
#include<cstring>
#include<algorithm>
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<string>
#include<utility>
#include<functional>


using namespace std;


int main() {
	
	ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
	int n;
	cin >> n;
	vector<int>v(n);

	for (int i = 0; i < n; i++) {
		cin >> v[i];
	}

	sort(v.begin(), v.end(), greater<int>());

	// 0,1,2,3,4,5,6,7,8,9,10,11,12 //2,5,8,11
	int total = 0;
	for (int i = 0; i < v.size(); i++) {

		if ((i % 3) != 2) {
			total += v[i];
		}
	}

	cout << total << endl;


}