#include <bits/stdc++.h>
#include "boxes.h"
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif
struct custom_hash {
static uint64_t splitmix64(uint64_t x) {
x += 0x9e3779b97f4a7c15;
x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
return x ^ (x >> 31);
}
size_t operator()(uint64_t x) const {
static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
return splitmix64(x + FIXED_RANDOM);
}
};
int dist(int x, int l){
return min(x, l - x);
}
ll delivery(int N, int K, int L, int P[]){
int n = N;
int k = K;
vi pos;
for(int i = 0; i < n; i++){
pos.pb(P[i]);
}
sort(all(pos));
vll l(n + 1, 0LL);
vll p(n + 1, 0LL);
for(int i = 0; i < min(n, k); i++){
l[i] = 2 * pos[i];
}
for(int i= k; i < n; i++){
l[i] = l[i - k] + 2 * pos[i];
}
for(int i = n - 1; i >= max(0, n - k); i--){
p[i] = 2 * (L - pos[i]);
}
for(int i = n - k - 1; i >= 0; i--){
p[i] = p[i + k] + 2 * (L - pos[i]);
}
ll ans = p[0];
for(int i = 0; i < n; i++){
ans = min(ans, (ll)l[i] + p[i + 1]);
}
return ans;
}
/*int main(){
int p[3] = {1, 2, 5};
cout << delivery(3, 2, 8, p);
return 0;
}*/
