#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
#define SZ(v) ((int)(v).size())
#define ALL(v) (v).begin(),(v).end()
#define one first
#define two second
typedef long long ll;
typedef pair<double, double> pd;
typedef pair<int, int> pi;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll; typedef pair<ll, pi> plp;
typedef tuple<int, int, int> ti; typedef tuple<ll, int, int> tli;
const int INF = 0x3f2f1f0f;
const ll LINF = 1ll * INF * INF * 2;
int N, K, L;
deque<int> Ps;
ll delivery(int n, int k, int l, int p[]) {
N = n; K = k; L = l;
for(int i=0; i<N; i++) Ps.push_back(p[i]);
while(SZ(Ps) > 0 && Ps.front() == 0) Ps.pop_front();
ll ans = 0;
while(SZ(Ps) > 0) {
int lix = min(K-1, SZ(Ps)-1);
if(Ps[lix] <= L/2) {
ans += Ps[lix] * 2;
for(int i=0; i<=lix; i++) Ps.pop_front();
}else break;
}
while(SZ(Ps) > 0) {
int rix = max(SZ(Ps)-K, 0);
if(Ps[rix] >= (L+1)/2) {
ans += (L - Ps[rix]) * 2;
for(int i=SZ(Ps)-1; i>=rix; i--) Ps.pop_back();
}else break;
}
if(SZ(Ps) > 0) {
int maxV = 0, minV = L;
for(int x : Ps) {
if(x <= L/2) maxV = max(maxV, x);
if(x >= (L+1)/2) minV = min(minV, x);
}
// printf("%d %d\n", maxV, minV);
int val = (maxV * 2 + (L - minV) * 2);
if(SZ(Ps) > K) {
int lix = K;
int rix = SZ(Ps) - K - 1;
ans += min(val, L + min(Ps[rix] * 2, (L - Ps[lix]) * 2));
}else{
ans += min(val, L);
}
}
return ans;
}
