#include "boxes.h" #include <bits/stdc++.h> long long delivery(int N, int K, int L, int p[]) { long long ans = 2E18; K = std::min(K, N); std::vector<long long> dist1, dist2; dist1.push_back(0), dist2.push_back(0); dist1.reserve(N / 2), dist2.reserve(N / 2); for (int i = 0; i < N; ++i) if (p[i] <= L / 2) dist1.push_back(p[i]); else dist2.push_back(L - p[i]); sort(dist1.begin(), dist1.end()), sort(dist2.begin(), dist2.end()); int a = (int)dist1.size(), b = (int)dist2.size(); std::vector<long long> pref1(a, 0), pref2(b, 0); for (int i = 1; i < a; ++i) pref1[i] = dist1[i] + ((i >= K) ? pref1[i - K] : 0); for (int i = 1; i < b; ++i) pref2[i] = dist2[i] + ((i >= K) ? pref2[i - K] : 0); ans = 2 * (pref1[a - 1] + pref2[b - 1]); for (int i = 1; i < K; ++i) if (K - i >= b) break; else ans = std::min(ans, L + 2 * (pref1[a - i - 1] + pref2[b - (K - i) - 1])); return ans; }