#include<bits/stdc++.h> #include "boxes.h" #define ll long long #define ld long double #define vl vector<ll> #define vi vector<int> #define all(v) v.begin(), v.end() #define rall(v) v.rbegin(), v.rend() #define f first #define s second #define pii pair<int, int> #define pll pair<ll, ll> #define f first #define s second using namespace std; long long delivery(int N, int K, int L, int p[]) { ll pos[N+1]; for(ll i = 1; i <= N; i++) pos[i] = p[i-1]; ll x[N+1], y[N+1]; x[0] = 0; for(ll i = 1; i <= N; i++) { if(i <= K) x[i] = pos[i] * 2; else x[i] = x[i-K] + pos[i] * 2; } y[N+1] = 0; for(ll i = N; i >= 1; i--) { if(N - i + 1 <= K) y[i] = (L - pos[i]) * 2; else y[i] = y[K+i] + (L - pos[i]) * 2; } ll res = min(x[N], y[1]); for(ll i = 1; i <= N - 1; i++) res = min(res, x[i] + y[i+1]); return res; }