#include "boxes.h"
// #pragma GCC target("avx2")
#pragma GCC optimize("O3", "unroll-loops")
// #include <bits/extc++.h>
// using namespace __gnu_pbds;
#include <bits/stdc++.h>
using namespace std;
#define int long long
// template <typename T>
// using pbds_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using pii = pair<int, int>;
template<typename T>
using prior = priority_queue<T, vector<T>, greater<T>>;
template<typename T>
using Prior = priority_queue<T>;
#define X first
#define Y second
#define fastIO() ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define RANDOM() random_device __rd; \
mt19937 __gen = mt19937(__rd()); \
uniform_int_distribution<int> __dis(0, 1); \
auto rnd = bind(__dis, __gen);
const int INF = 1E18;
const int mod = 1E9 + 7;
const int maxn = 1E6 + 5;
int delivery(int32_t N, int32_t K, int32_t L, int32_t POS[]) {
int n = N, k = K, l = L;
vector<int> pos(POS, POS + n);
int st[n], ed[n], minAns;
for (int i = 0; i < n; ++i) {
if (i < k) st[i] = min(2*pos[i], l);
else st[i] = st[i - k] + min(2*pos[i], l);
}
for (int i = n-1; i >= 0; --i) {
if (i >= n-k) ed[i] = min(2*(l-pos[i]), l);
else ed[i] = ed[i + k] + min(2*(l-pos[i]), l);
}
minAns = min(st[n - 1], ed[0]);
for (int i = 0; i < n-1; ++i) minAns = min(minAns, st[i] + ed[i + 1]);
return minAns;
}
/*
int32_t main() {
fastIO();
return 0;
}*/
