Submission #668397

#	Time	Username	Problem	Language	Result	Execution time	Memory
668397		600Mihnea	Safety (NOI18_safety)	C++17	35 / 100	144 ms	724 KiB

safety

#include <bits/stdc++.h>


using namespace std;

#define int long long

const int N = 5000 + 7;
const int INF = (int) 1e18 + 7;
int n, dmax, a[N], dp[N], ndp[N];

signed main()
{
#ifdef ONPC
  freopen ("input.txt", "r", stdin);
#endif // ONPC

#ifndef ONPC
  ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif // ONPC

  cin >> n >> dmax;

  for (int i = 1; i <= n; i++)
  {
    cin >> a[i];
  }

  int big = *max_element(a + 1, a + n + 1);

  if (*max_element(a + 1, a + n + 1) <= dmax)
  {
    cout << "0\n";
    return 0;
  }

  assert(n < N && dmax < N);

  for (int x = 0; x <= big; x++)
  {
    dp[x] = abs(x - a[1]);
  }

  for (int step = 2; step <= n; step++)
  {
    deque<int> d;
    int y = 0;
    for (int x = 0; x <= big; x++)
    {
      while (y <= big && y <= x + dmax)
      {
        while (!d.empty() && dp[d.back()] > dp[y])
        {
          d.pop_back();
        }
        d.push_back(y);
        y++;
      }
      assert(!d.empty());
      if (!d.empty() && d.front() < x - dmax)
      {
        d.pop_front();
      }
      assert(!d.empty());
      assert(abs(x - d.front()) <= dmax);
      ndp[x] = dp[d.front()] + abs(a[step] - x);
    }
    for (int x = 0; x <= big; x++)
    {
      dp[x] = ndp[x];
    }
  }
  int best = dp[0];
  for (int x = 0; x <= big; x++)
  {
    best = min(best, dp[x]);
  }
  cout << best << "\n";

  return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 4 / 4
• Subtask 3: 0 / 9
• Subtask 4: 0 / 5
• Subtask 5: 6 / 6
• Subtask 6: 11 / 11
• Subtask 7: 11 / 11
• Subtask 8: 0 / 22
• Subtask 9: 0 / 29