#ifndef boxes_h
#define boxes_h
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
long long delivery(int n, int k, int l, int P[]) {
vector<ll> p;
for(int i = 0; i < n; i ++ ) p.push_back(P[i]);
vector<ll> pr(n+1, 0), sf(n+1, 0);
for(int i = 0; i < n; i ++ ) {
if(i < k) pr[i] = p[i];
if(i >= k) pr[i] += pr[i-k] + p[i-k] + p[i];
};
for(int i = n-1; i >= 0; i -- ) {
if(i + k >= n)sf[i] = l-p[i];
if(i + k < n)sf[i] += sf[i+k] + l-p[i+k] + l-p[i];
};
ll ans = pr[n-1] + min(l-p[n-1], p[n-1]);
ans = min(ans, sf[0] + min(l-p[0], p[0]));
for(int i = 1; i < n; i ++ ) {
ans = min(ans, pr[i-1] + sf[i] + min(p[i], l-p[i]) + min(p[i-1], l-p[i-1]));
};
return ans;
};
#endif
