#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
const int nax = 1e3 + 3;
const long long INF = 1e18;
long long dp[nax];
int n, k, L;
int a[nax];
int c[nax];
int get(int i, int j) {
if(i==j) return 0;
return min(a[j]-a[i], c[i]+c[i+1]+a[j]-a[i+1]);
}
long long delivery(int N, int K, int l, int p[]) {
n = N, k = K, L = l;
for(int i=1; i<=n; ++i) {
a[i] = p[i-1];
c[i] = min(a[i], L-a[i]);
}
for(int i=1; i<=n+1; ++i) {
dp[i] = INF;
}
dp[1] = c[1];
for(int i=1; i<=n; ++i) {
for(int j=0; j<k && i+j+1<=n; ++j) {
dp[i+j+1] = min(dp[i+j+1], dp[i] + get(i, i+j) + c[i+j] + c[i+j+1]);
}
}
long long ans = INF;
for(int i=1; i<=n; ++i) {
if(i+k-1>=n) {
ans = min(ans, L-a[i]+dp[i]);
if(a[i]==a[n]) ans = min(ans, a[i]+dp[i]);
}
}
return ans;
}
