#include "boxes.h" #include <bits/stdc++.h> #define ll long long using namespace std; const ll inf = 1e7+9,MX = 1e18+9; ll predir1[inf],predir2[inf],add[inf]; ll delivery(int n, int k, int l, int p[]) { ll ret = MX; sort(p,p+n); for(int i=0;i<n;i++){ add[i%k] += p[i] + min(l-p[i],p[i]); predir1[i] = add[i%k]; } for(int i=0;i<k;i++) add[i] = 0; ll cnt=0; for(int i=n-1;i>=0;i--){ add[cnt%k] += (l-p[i]) + min(l-p[i],p[i]); predir2[i] += add[cnt%k]; cnt++; } for(int i=-1;i<n;i++){ ll tmp=0; if( i != -1) tmp+=predir1[i]; if(i != n-1) tmp+=predir2[i+1]; ret = min(ret , tmp); } return ret; }