#include <bits/stdc++.h>
using namespace std;
vector<long long> get(vector<int> a, int k) {
if (a.empty()) return {};
int n = a.size();
vector<long long> dp(n);
for (int i = 0; i < min(n, k); i++) {
dp[i] = a[i] * 2;
}
for (int i = k; i < n; i++) {
dp[i] = dp[i - k] + a[i] * 2;
}
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);
auto x = get(l, k);
auto 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 = (l.size() == i ? 0 : x[x.size() - 1 - i]);
long long rhs = (r.size() == k - i ? 0 : y[y.size() - 1 - k + i]);
mn = min(mn, lhs + rhs + len);
}
ans = min(ans, mn);
return ans;
}
