#include "boxes.h"
#include<vector>
#include<cstdio>
#include<algorithm>
using namespace std;
#define pb push_back
#define sz(a) (int)(a.size())
using ll = long long;
ll delivery(int N, int K, int L, int p[]) {
vector<int> esq = {0}, dir;
for(int i = 0; i < N; i++) {
if(!p[i]) continue;
if(p[i] <= L/2)
esq.pb(p[i]);
if(p[i] >= L - (L-1)/2)
dir.pb(L - p[i]);
}
dir.pb(0);
reverse(dir.begin(), dir.end());
vector<ll> pref(sz(esq)), suf(sz(dir));
for(int i = 1; i < sz(esq); i++)
pref[i] = 2ll*esq[i] + (i>=K?pref[i-K]:0);
for(int i = 1; i < sz(dir); i++)
suf[i] = 2ll*dir[i] + (i>=K?suf[i-K]:0);
ll ans = (sz(pref)?pref.back():0) + (sz(suf)?suf.back():0);
for(int i = 0; i <= min(K, sz(esq)-1); i++) {
ll here = L + pref[sz(esq)-1-i];
here += suf[max(0, sz(dir)-1-(K-i))];
ans = min(ans, here);
}
return ans;
}
