#include <bits/stdc++.h>
using namespace std;
vector<long long> get(vector<int> a, int k) {
if (a.empty()) return {0};
int n = a.size();
multiset<long long> s;
vector<long long> dp(n + 1);
for (int i = 0; i < min(n, k); i++) {
dp[i + 1] = a[i] * 2;
s.insert(dp[i]);
}
for (int i = k; i < n; i++) {
dp[i + 1] = *s.begin() + a[i] * 2;
s.erase(s.find(dp[i + 1 - k]));
s.insert(dp[i + 1]);
}
return dp;
}
long long delivery(int n, int k, int len, int p[]) {
vector<int> pos(n);
for (int i = 0; i < n; i++) {
pos[i] = p[i];
}
n = pos.size();
vector<int> l, r;
for (int i = 0; i < n; i++) {
if (pos[i] <= len / 2) {
l.push_back(pos[i]);
} else {
r.push_back(len - pos[i]);
}
}
ranges::reverse(r);
vector<long long> x = get(l, k);
vector<long long> y = get(r, k);
long long ans = 0;
if (!x.empty()) ans += x.back();
if (!y.empty()) ans += y.back();
long long mn = 1e18;
for (int i = 0; i <= k; i++) {
if (l.size() < i) continue;
if (r.size() < k - i) continue;
long long lhs = x[x.size() - i - 1];
long long rhs = y[y.size() - k + i - 1];
mn = min(mn, len + lhs + rhs);
}
ans = min(ans, mn);
return ans;
}
