11508번 - 2+1 세일

https://www.acmicpc.net/problem/11508

11508번: 2+1 세일

#include <iostream>

#include <algorithm>

using namespace std;

#define endl '\n'

bool compare(int i, int j)

{

  return j < i;

}

int main() {

 

  int N, sum = 0;

  cin >> N;

  int price[100001] = {0, };

  for(int i=0; i<N; i++)

    cin >> price[i];

 

  sort(price, price+N, compare);

 

  for(int i=0; i<N; i++)

    if(i % 3 != 2)

      sum += price[i];

  cout << sum << endl;

  return 0;

}