#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const int mxN = 1005;
ll memo[mxN][mxN][3];
int L;
int n;
int k;
vector<int> pos;
ll solve(int l, int cnt, int t) {
int r = (l+n-1)-cnt;
//cout << l << " " << r << " " << cnt << endl;
if (cnt==n) return 0;
if (memo[l][cnt][t] != -1) return memo[l][cnt][t];
ll result = 1e18;
int idx;
if (cnt%k==0) {
idx=0;
}
else {
if (t==0) {
idx=0;
}
else if (t==1) {
idx = pos[l-1];
}
else {
idx = pos[r+1];
}
}
//Caso voy a l
ll extra = (((cnt+1)%k==0 || (cnt+1)==n) ? min(pos[l], abs(L-pos[l])) : 0);
ll costl;
if (idx <= pos[l]) costl = pos[l]-idx;
else costl = idx+pos[l];
costl += extra;
result = min(result, costl+solve(l+1, cnt+1, 1));
//Caso voy desde r
extra = (((cnt+1)%k==0 || (cnt+1)==n) ? min(pos[r], abs(L-pos[r])) : 0);
ll costr;
if (idx >= pos[r]) costr = idx-pos[r];
else costr = idx+L-pos[r];
costr += extra;
result = min(result, costr+solve(l, cnt+1, 2));
memo[l][cnt][t] = result;
return result;
}
ll delivery(int N, int K, int l, int* a) {
n = N;
k = K;
L = l;
pos.assign(n, 0);
for (int i=0; i<n; i++) {
pos[i] = a[i];
}
memset(memo, -1, sizeof(memo));
return solve(0, 0, 0);
}
