#include <bits/stdc++.h> using namespace std; #define MOD1 1000000007 #define MOD2 998244353 #define fir first #define sec second #define pushf push_front #define pushb push_back #define popf pop_front #define popb pop_back #define mp make_pair #define all(a) a.begin(), a.end() #define lbound(v, x) lower_bound(all(v), x) - v.begin() #define ubound(v, x) upper_bound(all(v), x) - v.begin() #define chmax(a, b) a = max(a, b) #define chmin(a, b) a = min(a, b) #define FOR1(a) for (int _ = 0; _ < (a); ++_) #define FOR2(i, a) for (int i = 0; i < (a); ++i) #define FOR3(i, a, b) for (int i = (a); i < (b); ++i) #define RFOR1(a) for (int _ = (a)-1; _ >= 0; --_) #define RFOR2(i, a) for (int i = (a)-1; i >= 0; --i) #define RFOR3(i, a, b) for (int i = (b)-1; i >= (a); --i) #define overload3(a, b, c, d, ...) d // Always choose the fourth argument to call. Hence, which function to call is determined by the number of given arguments. #define REP(...) overload3(__VA_ARGS__, FOR3, FOR2, FOR1)(__VA_ARGS__) #define RREP(...) overload3(__VA_ARGS__, RFOR3, RFOR2, RFOR1)(__VA_ARGS__) typedef long long ll; typedef pair<int, int> pii; typedef vector<int> vi; typedef pair<ll, ll> pll; typedef vector<ll> vll; typedef vector<bool> vb; typedef vector<char> vc; typedef vector<string> vs; typedef vector<pii> vpii; typedef vector<pll> vpll; typedef vector<vi> vvi; typedef vector<vll> vvll; typedef vector<vb> vvb; typedef vector<vc> vvc; typedef vector<vpii> vvpii; typedef vector<vpll> vvpll; typedef queue<int> qi; typedef queue<ll> qll; typedef queue<pii> qpii; typedef queue<pll> qpll; typedef deque<int> dqi; typedef deque<ll> dqll; typedef deque<pii> dqpii; typedef deque<pll> dqpll; typedef priority_queue<int> pqi; typedef priority_queue<ll> pqll; typedef priority_queue<pii> pqpii; typedef priority_queue<pll> pqpll; typedef priority_queue<int, vi, greater<int> > r_pqi; typedef priority_queue<ll, vll, greater<ll> > r_pqll; typedef priority_queue<pii, vpii, greater<pii> > r_pqpii; typedef priority_queue<pll, vpll, greater<pll> > r_pqpll; int main() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); ll n, h; cin >> n >> h; ll l = 0, r = 0, pos = 0; // L and R are the left and right half of the slope (decreasing and increasing gradient) pqll L, R; ll ans = 0; for (int i = 1; i <= n; ++i) { ll a; cin >> a; if (a >= pos) { R.push(-a+r); R.push(-a+r); // rebalances R L.push(-R.top()+r-l); R.pop(); ans += a-L.top()-l; } else { L.push(a-l); L.push(a-l); // rebalances L R.push(-L.top()-l+r); L.pop(); ans += -R.top()+r-a; } // f'(x) = f(y) for abs(x-y) < h is as good as expanding the left and right half of the slope by h. l -= h; r += h; pos = L.top()+l; } cout << ans << endl; }