| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1249107 | Chris_Black | Safety (NOI18_safety) | C++20 | 0 ms | 0 KiB |
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx2")
#include <bits/stdc++.h>
#define ll long long
#define vi vector<int>
#define vvi vector<vi>
#define pb push_back
#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 pii pair<int, int>
#define ff first
#define ss second
#define pll pair<ll, ll>
#define vpi vector<pii>
#define vvpi vector<vpi>
#define vpl vector<pll>
#define vvpl vector<vpl>
#define vl vector<ll>
#define vvl vector<vl>
//#define x first
//#define y second
using namespace std;
const int N = 1e6 + 9, LGV = 33, LGN = 21, Mod = 1e9 + 7;
//const int Inf = 0x3f3f3f3f;
const ll Inf = LLONG_MAX / 2;
const bool test_case = false;
//ifstream fin("landscape.in");
//ofstream fout("landscape.out");
//#define cin fin
//#define cout fout
int n, h, a[N];
ll addl, addr;
priority_queue<ll> l;
priority_queue<ll, vi, greater<>> r;
void rebalance()
{
while(l.size() > r.size())
{
r.push(l.top() + addl - addr);
l.pop();
}
while(r.size() > l.size())
{
l.push(r.top() + addr - addl);
r.pop();
}
}
void add(ll x)
{
if(l.empty() || x <= l.top() + addl)
l.push(x - addl);
else r.push(x - addr);
rebalance();
}
void solve()
{
cin >> n >> h;
FOR(i, 1, n)cin >> a[i];
ll ans = 0;
FOR(i, 1, n)
{
addl -= h, addr += h;
if(i > 1)
{
ll lp = l.top() + addl, rp = r.top() + addr;
if(a[i] < lp)ans += lp - a[i];
else if(a[i] > rp)ans += a[i] - rp;
}
add(a[i]);
add(a[i]);
}
cout << ans << '\n';
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
int t = 1;
if(test_case)cin >> t;
while(t --)solve();
return 0;
}