#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace std; using namespace __gnu_pbds; typedef long long ll; typedef long double ld; #define ppf pop_front #define ppb pop_back #define pf push_front #define pb push_back #define fr first #define sc second #define mnto(x,y) x = min(x, (__typeof__(x))y) #define mxto(x,y) x = max(x, (__typeof__(x))y) #define setval(arr, x) memset(arr, x, sizeof(arr)) template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int n; ll h; cin >> n >> h; priority_queue<ll> lq; priority_queue<ll, vector<ll>, greater<ll>> rq; ll ans = 0; for (int i = 0; i < n; ++i) { ll a; cin >> a; if (i == 0) { lq.push(a); rq.push(a); continue; } ll range = (ll)i * h; if (a + range < lq.top()) { lq.push(a + range); ans += lq.top() - a - range; ll topv = lq.top(); lq.pop(); lq.push(a + range); rq.push(topv - range * 2ll); } else if (a - range > rq.top()) { rq.push(a - range); ans += a - range - rq.top(); ll topv = rq.top(); rq.pop(); rq.push(a - range); lq.push(topv + range * 2ll); } else { lq.push(a + range); rq.push(a - range); } } cout << ans; }