#ifdef NYAOWO
#include "grader.cpp"
#endif
#include "boxes.h"
#include <bits/stdc++.h>
#define For(i, a, b) for(int i = a; i <= b; i++)
#define Forr(i, a, b) for(int i = a; i >= b; i--)
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define sz(x) ((int)x.size())
#define eb emplace_back
#define int LL
using namespace std;
using LL = long long;
using pii = pair<int, int>;
const int INF = 1'000'000'000'000'000'000;
long long delivery(int32_t N, int32_t K, int32_t L, int32_t pos[]) {
int dp = 0;
deque<pii> dq; // {index, value}
For(i, 1, N) {
int a = pos[i - 1];
int c = min(a, L - a);
if(sz(dq) && dq.front().F <= i - K) dq.pop_front();
int val = dp + c - a;
while(sz(dq) && dq.back().S > val) dq.pop_back();
dq.eb(i, val);
dp = a + c + dq.front().S;
}
return dp;
}
