For this Question: Given an array Arr of N integers. You can do an operation on the array:
In one operation, you can select exactly 4 elements from the array, and add the second smallest element of those 4 to your happiness. For example: if you select W, X, Y, Z where W <= X <= Y <= Z, you get X amount of happiness. Remove the 4 elements from the array.

Find the maximum amount of happiness you can get from the array, if you can perform the operations as many times as the constraints permit.

Note: You cannot choose elements if the remaining array size is less than 4.First line of input contains a single integer N.
Second line of input contains N integers, denoting array Arr.

Constraints:
1 <= N <= 100000
1 <= Arr[i] <= 1000000000

N is always divisible by 4.Output the maximum amount of happiness you can get.Sample Input 1
4
2 1 2 4

Sample Output 1
2

Explanation: We select the values 1 2 2 4 and get second highest happiness which is 2.

Sample Input 2
8
7 3 5 5 2 1 1 7 

Sample Output 2
7, I have written this Solution Code: #pragma GCC optimize ("Ofast")
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define VV vector
#define pb push_back
#define bitc  __builtin_popcountll
#define m_p make_pair
#define infi 1e18+1
#define eps 0.000000000001
#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);
string char_to_str(char c){string tem(1,c);return tem;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<class T>//usage rand<long long>()
T rand() {
    return uniform_int_distribution<T>()(rng);
}
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// string to integer stoi()
// string to long long stoll()
// string.substr(position,length);
// integer to string to_string();
 
//////////////
auto clk=clock();
#define all(x) x.begin(),x.end()
#define S second
#define F first
#define sz(x) ((long long)x.size())
#define int long long  
#define f80 __float128
#define pii pair<int,int>
/////////////

signed main()
{
	fastio;
	#ifdef ANIKET_GOYAL
		freopen("inputf.in","r",stdin);
		freopen("outputf.in","w",stdout);
	#endif
	int n;
	cin>>n;
	int a[n];
	for(int i=0;i<n;++i){
		cin>>a[i];
	}	sort(a,a+n);
	int ans=0;
	for(int i=1;i<=n/4;++i){
		ans+=a[n-i*3];
	}
	cout<<ans;
}, In this Programming Language: C++, Now tell me if this Code is compilable or not?