#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
/*⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣤⠀⠀⠀⠀⠀⠀⠀⡄⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣤⣿⠛⣿⠀⠀⠀⠀⣤⣿⢻⡇⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣤⣿⡛⠀⣤⣿⣿⣤⣤⣿⣿⣤⢸⡇⠀
⠀⠀⠀⠀⠀⠀⠀⠀⣴⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡇⠀
⠀⠀⠀⠀⠀⠀⠀⣶⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡗⠀
⢠⣼⣿⣿⣿⣿⣤⣾⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷
⢸⣿⣿⡟⠛⠛⢿⣿⣿⣿⣿⣿⣿⣿⣤⣤⣤⣿⣿⣿⣿⣤⣤⣼⣿⣿
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⠛⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⡟⠋
*/
#define fi first
#define se second
#define pb push_back
#define ins insert
#define sz(a) (int)(a.size())
#define all(x) (x).begin(),(x).end()
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
void print(){cout<<'\n';}
template<class h,class...t>
void print(const h&v,const t&...u){cout<<v<<' ',print(u...);}
#define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
#include "debug.h"
#else
#define debug(...)
#endif
//const int mod = 1e9+7;
//const int mod = 998244353;
const int MAXN=2e5+5;
const ll inf=1e9,INF=1e18;
long long delivery(int N, int K, int L, int p[]) {
ll pref[N + 1],suff[N + 2], ans = INF; pref[0] = suff[N+1] = 0;
for(int i=1;i<=N;i++) pref[i] = pref[max(0,i-K)] + 2ll * p[i-1];
for(int i=N;i>0;i--) suff[i] = suff[min(N+1,i+K)] + 2ll * (L - p[i-1]);
for(int i=0;i<=N;i++) ans = min({ans,pref[i] + suff[i+1],pref[i] + suff[min(N+1,i+K+1)] + L});
return ans;
}
// signed main() {
// int p[] = {1,3,4,5};
// print(delivery(4,2,8,p));
// }
