#include <bits/stdc++.h>
#include <iostream>
#include "boxes.h"
using namespace std;
#define rep(i,a,b) for(int i = a; i < b; i++)
#define pb push_back
#define lso(x) x&(-x)
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
int n, k, l;
vi p;
vi pos;
ll min(ll a, int b) {return min(a, (ll)b);}
ll kone() {
ll ans = 0;
rep(i,0,n) {
ans += 2*min(pos[i], l - pos[i]);
}
return ans;
}
ll kn() {
ll ans = l;
ans = min(ans, 2*(l - pos[0]));
ans = min(ans, 2*pos[n - 1]);
rep(i,0,n - 1) {
ans = min(ans, 2*pos[i] + 2*(l - pos[i + 1]));
}
return ans;
}
ll ev(int ss) {
ll ans = 0;
int fhc = l / 2;
int shc = l / 2 + (l & 1);
int a = 0, b = 0;
while (a < n) {
if (ss&(1<<a)) while (ss&(1<<b) && b < n) {b++;}
else while (!(ss&(1<<b)) && b < n) {b++;}
b--;
if (b - a >= k) return 1e18;
if (pos[b] <= fhc) ans += 2*pos[b];
else if (pos[a] >= shc) ans += 2*(l - pos[a]);
else {
int low = a, high = b + 1, c = low;
while (high - low > 1) {
c = (high + low) / 2;
if (pos[c] >= shc) high = c;
else low = c;
}
ll cand1 = l, cand2 = 2*pos[c] + 2*(l - pos[c + 1]);
ans += min(cand1, cand2);
}
a = b = b + 1;
}
return ans;
}
ll n10() {
ll ans = 1e18;
rep(ss, 0, pow(2, n)) ans = min(ans, ev(ss));
return ans;
}
ll delivery(int N, int K, int L, int positions[]) {
n = N; k = K; l = L;
pos.resize(n); rep(i,0,n) pos[i] = positions[i];
if (k == 1) return kone();
else if (k == n) return kn();
else if (n <= 14) return n10();
return 0;
}
// int main() {
// int a = 3, b = 2, c = 8;
// int pp[3] = {1, 1, 7};
// cout << delivery(a, b, c, pp);
// }
