#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 1e7 + 5;
int n, k, l;
int a[maxn];
vector<int> solve() {
int cnt[k];
for (int i=0;i<k;i++) cnt[i] = 0;
vector<int> cost(n);
for (int i=0;i<n;i++) {
cnt[i%k] += min(a[i] * 2, l);
cost[i] = cnt[i%k];
}
return cost;
}
long long delivery(int32_t N, int32_t K, int32_t L, int32_t p[]) {
k = K, l = L;
n = 0;
for (int i=0;i<N;i++) {
if (p[i]!=0) a[n] = p[i], n++;
}
if (n==0) return (int)0;
sort(a, a+n);
vector<int> fwd = solve();
for (int i=0;i<n;i++) a[i] = L - a[i];
reverse(a, a+n);
// for (int i=0;i<n;i++) cout << a[i] << " "; cout << endl;
vector<int> bwd = solve();
reverse(bwd.begin(), bwd.end());
// for (int i=0;i<n;i++) cout << fwd[i] << " "; cout << endl;
// for (int i=0;i<n;i++) cout << bwd[i] << " "; cout << endl;
int ans = min(fwd[n-1], bwd[0]);
for (int i=0;i<n-1;i++) ans = min(fwd[i] + bwd[i+1], ans);
// cout << ans << endl;
return ans;
}
