Help me in solving TWINGFT problem

help
,
1

My issue

My code

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl "\n"
#define fast ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
int main(){
    fast
    int t;cin>>t;
    while(t--){
        int n,k;cin>>n>>k;
        vector<int>l(n);
        ll sum=0;
        for(int i=0;i<n;i++){
            cin>>l[i];
        }
        sort(l.rbegin(),l.rend());
        for(int i=0;i<n-1;i+=2){
            sum+=l[i];
        }
        ll sum1=l[n-1];
        for(int i=1;i<=n-1;i+=2){
            sum1+=l[i];
        }
        cout<<max(sum,sum1)<<endl;
    } 
}

Problem Link: TWINGFT Problem - CodeChef