#include "boxes.h" #include <bits/stdc++.h> long long delivery(int N, int K, int L, int p[]) { long long ans; int it = std::lower_bound(p, p + N, (L + 1) / 2) - p; auto get_prf = [&](int i) { long long res = 0; for (; i >= 0; i -= K) res += 2 * p[i]; return res; }; auto get_suf = [&](int i) { long long res = 0; for (; i < N; i += K) res += 2 * (L - p[i]); return res; }; ans = get_prf(it - 1) + get_suf(it); for (int i = std::max(0, it - K); i < it; i++) ans = std::min(ans, (long long)get_prf(i - 1) + L + get_suf(i + K)); return ans; }