#include <bits/stdc++.h> #define ll long long using namespace std; int main() { ios::sync_with_stdio(0), cin.tie(0); int n; ll k; cin >> n >> k; ll shf = 0, ans = 0; multiset <ll> L, R; while (n--) { ll x; cin >> x; if (L.size() && *prev(L.end()) - shf > x) { L.emplace(x+shf); ans += *prev(L.end()) - shf - x; L.emplace(x+shf); auto it = prev(L.end()); ll y = *it; L.erase(it); y -= 2*shf; R.emplace(y); } else if (R.size() && *R.begin() + shf < x) { R.emplace(x-shf); ans += x - (*R.begin() + shf); R.emplace(x-shf); auto it = R.begin(); ll y = *it; R.erase(it); y += 2*shf; L.emplace(y); } else { L.emplace(x+shf); R.emplace(x-shf); } shf += k; } cout << ans << '\n'; }