#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
#define name "boxes"
#define MAXN 10000007
#define pb push_back
#define pf push_front
#define ll long long
#define ii pair<int, int>
#define fs first
#define sc second
#define ill pair<int, ll>
#define lli pair<ll, int>
#define llll pair<ll, ll>
#define all(v) v.begin(),v.end()
#define uni(v) v.erase(unique(all(v)),v.end())
#define bit(n,i) (((n)>>(i))&1)
#define FOR(i,a,b) for (int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for (int i=(a),_b=(b); i>=_b; i--)
#define MASK(i) (1LL<<(i))
const int INF=1e9;
const int MOD=1e9+7;
void add(int &u, int v){
u+=v;
if (u>=MOD) u-=MOD;
}
void sub(int &u, int v){
u-=v;
if (u<0) u+=MOD;
}
void minimize(int &u, int v){
u=min(u,v);
}
void maximize(int &u, int v){
u=max(u,v);
}
long long Rand(long long l, long long r){
ll tmp=0;
FOR(i,1,4) tmp=((tmp<<15)^(((1<<15)-1)&rand()));
return l+tmp%(r-l+1);
}
ll delivery(int n, int k, int L, int positions[]){
int mid=-1;
FOR(i,0,n-1){
if (positions[i]<=L/2){
mid=i;
}
}
int l=0,r=0;
int u=n-1,v=n-1;
while (l<=n-1&&positions[l]==0) ++l;
r=l;
ll ans=0;
while (1){
while (r<mid&&r-l+1<k){
++r;
}
while (v>mid+1&&u-v+1<k){
--v;
}
if (r-l+1==k&&u-v+1==k){
if (positions[r]*2<=(L-positions[v])*2){
ans+=1LL*positions[r]*2;
l=++r;
}
else{
ans+=1LL*(L-positions[v])*2;
u=--v;
}
}
else if (r-l+1==k){
ans+=1LL*positions[r]*2;
l=++r;
}
else if (u-v+1==k){
ans+=1LL*(L-positions[v])*2;
u=--v;
}
else{
break;
}
}
if (r>mid&&v==mid) return ans;
if (r>mid){
return ans+1LL*(L-positions[r])*2;
}
else if (v==mid){
return ans+1LL*positions[v]*2;
}
int kq=2*INF;
if (r<=mid){
int _l=l,_r=r;
while (r-l+1<k&&r<u) ++r;
if (r-l+1<k){
minimize(kq,L);
}
else{
if (r==u) minimize(kq,L);
else minimize(kq,L+(L-positions[r+1])*2);
}
l=_l,r=_r;
}
if (v>mid){
int _u=u,_v=v;
while (u-v+1<k&&v>r) --v;
if (u-v+1<k) minimize(kq,L);
else{
if (v==r) minimize(kq,L);
else minimize(kq,L+positions[v-1]*2);
}
u=_u,v=_v;
}
return ans+1LL*kq;
}
