#include "boxes.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define X first
#define Y second
#define debug(x) cerr << #x << ": " << x << endl;
const ll MAXN = 2e7 + 10;
ll ps[MAXN], ss[MAXN];
long long delivery(int N, int K, int L, int p[]) {
sort(p, p + N);
deque<pll> dq;
dq.push_back({0, -1});
for (int i = 0; i < N; i++) {
while (dq.front().Y < i - K) dq.pop_front();
ps[i] = numeric_limits<ll>::max();
ps[i] = min(ps[i], dq.front().X + p[i] + min(L - p[i], p[i]));
while (!dq.empty() && dq.back().X >= ps[i]) dq.pop_back();
dq.push_back({ps[i], i});
}
while (!dq.empty()) dq.pop_back();
ss[N] = 0;
dq.push_back({0, N});
for (int i = N - 1; i >= 0; i--) {
while (dq.front().Y > i + K) dq.pop_front();
ss[i] = numeric_limits<ll>::max();
ss[i] = min(ss[i], dq.front().X + (L - p[i]) + min(L - p[i], p[i]));
while (!dq.empty() && dq.back().X >= ss[i]) dq.pop_back();
dq.push_back({ss[i], i});
}
ll ans = min(ps[N - 1], ss[0]);
for (int i = 0; i < N; i++)
ans = min(ans, ps[i] + ss[i + 1]);
return ans;
}
