#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
long long delivery(int N, int K, int L, int p[]) {
vector<ll> V;
for(int i=0;i<N;i++){
if(p[i]!=0) V.push_back(p[i]);
}
if(V.empty()) return 0;
sort(V.begin(),V.end());
N = V.size();
vector<ll> dpl(N,0), dpr(N,0);
for(int i=0;i<N;i++){
if(i<K) dpl[i]=2*V[i];
else dpl[i]=dpl[i-K]+2*V[i];
}
for(int i=N-1;i>=0;i--){
if(N-1-i<K) dpr[i]=2*(L-V[i]);
else dpr[i]=dpr[i+K]+2*(L-V[i]);
}
ll ans = LLONG_MAX;
for(int i=0;i+1<N;i++){
ans = min(ans, dpl[i] + dpr[i+1]);
}
for(int i=0;i+K+1<N;i++){
ans = min(ans, dpl[i] + dpr[i+K+1] + L);
}
ans = min(ans, dpl[N-1]);
ans = min(ans, dpr[0]);
if(N<=K) ans = min(ans, (ll)L);
return ans;
}
