#include "boxes.h"
#include<bits/stdc++.h>
using namespace std;
using ll=long long;
const ll LINF=(1LL<<60)-1LL;
ll ddiv(ll a,ll b){
return a/b+(a%b>0);
}
long long delivery(int N, int K, int L, int p[]) {
ll res=L*ddiv(N,K);
vector<ll> a(K),b(K),c(N),d(N);
for(ll j=N-1;j>=0;j--){
b[(N-j-1)%K]+=2LL*(L-p[j]);
d[j]=b[(N-j-1)%K];
res=min(res,b[(N-j-1)%K]+L*ddiv(j,K));
}
for(ll i=0;i<N;i++){
a[i%K]+=2LL*p[i];
c[i]=a[i%K];
res=min(res,a[i%K]+L*ddiv(N-i-1,K));
}
res=min(res,d[0]);
for(int i=0;i<N;i++){
if(i<N-1){
res=min(res,c[i]+d[i+1]);
}else{
res=min(res,c[i]);
}
}
for(int i=0;i<N;i++){
if(i+K+1<N){
res=min(res,c[i]+d[i+K+1]+L);
}
}
for(int i=0;i<N;i++){
if(i+2*K+1<N){
res=min(res,c[i]+d[i+K+K+1]+2LL*L);
}
}
return res;
}
