1920B - Summation Game - CodeForces Solution

#include <bits/stdc++.h>

using namespace std;

void solve(){
    int n, k ,x;
    cin >> n >> k >> x;
    int a[n];
    for (int i = 0; i < n ; i++){
        cin >> a[i];
    }
    sort ( a, a + n);
    for (int i = 1; i < n ; i++){
        a[i] += a[i-1];
    }
    int ans = -a[n-1];
    for (int i = k; i >= 0 ; i--){
        if ( i == n){
            ans = max(ans,0);
        }else{
            if (n - i - x - 1 < 0){
                ans = max(ans, -a[n-i-1]);
            }else{
                ans = max(ans,2 *a[n-i-x-1]- a[n - i - 1]);
            }
        }
    }
    cout << ans << endl;
}

int main(){
    int t;
    cin >> t;
    while(t--){
        solve();
    }
}