help mik c++ .......................

$\color{#1fdb91}{\texttt{C}}\color{#0aaec9}{\texttt{+}}\color{#e9418e}{\texttt{+}}$

#include <bits/stdc++.h>

#define ll long long

using namespace std;

int main() {
    
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    
    ll n, k; cin >> n >> k;
    vector<ll> a(n);
    
    for(ll& i:a) cin >> i;
    sort(a.begin()+1, a.end(), greater<ll>());
    
    ll res=a[0];
    for (ll i=1; i<=k; ++i) res += a[i];
    for (ll i=k+1; i<n; ++i) res -= a[i];
    
    cout << res;
    
}

$\\$
\begin{array}{c|c|c}\color{#ffd710}{\texttt{\{}} \color{#8655d6}{\texttt{\{}}\ \ \color{#8cdcda}{\text{Daoanhviet96}}\ \ \color{#8655d6}{\texttt{\}}} \color{#ffd710}{\texttt{\}}}\end{array}

#include <iostream>
#include <algorithm>
using namespace std;
int main() {
    long long n,k;
    cin >> n >> k;
    long long a[n];
    for (long long i=0; i<n; i++) cin >> a[i];
    sort(a,a+n,greater<long long>());
    long long ans=a[0];
    for (long long i=1; i<=n-k-1; i++) ans+=a[i];
    for (long long i=k+1; i<n; i++) ans-=a[i];
    cout << ans;
}