Submission #668251

#	Time	Username	Problem	Language	Result	Execution time	Memory
668251		600Mihnea	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	18 / 100	25 ms	10448 KiB

mushrooms

#include <bits/stdc++.h>


using namespace std;

int 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

  int n, m, r, need;
  cin >> n >> m >> r >> need;
  vector<pair<int, int>> mus, spr;
  for (int i = 0; i < n; i++)
  {
    string s;
    cin >> s;
    assert((int) s.size() == m);
    for (int j = 0; j < m; j++)
    {
      char ch = s[j];
      if (ch == '.')
      {
        continue;
      }
      if (ch == 'S')
      {
        spr.push_back({i, j});
        continue;
      }
      if (ch == 'M')
      {
        mus.push_back({i, j});
        continue;
      }
      assert(0);
    }
  }
  int sol = 0;
  sort(mus.begin(), mus.end());
  sort(spr.begin(), spr.end());
  int p1 = 0, p2 = 0;

  int dim = m + 7;
  vector<int> t(dim, 0);

  auto add = [&] (int pos, int x)
  {
    pos++;
    for (int i = pos; i < dim; i += i & (-i))
    {
      t[i] += x;
    }
  };

  auto get = [&] (int pos)
  {
    pos++;
    int sol = 0;
    for (int i = pos; i >= 1; i -= i & (-i))
    {
      sol += t[i];
    }
    return sol;
  };

  for (auto &it : mus)
  {
    while (p1 < (int) spr.size() && spr[p1].first <= it.first + r)
    {
      add(spr[p1++].second, +1);
    }
    while (p2 < (int) spr.size() && spr[p2].first < it.first - r)
    {
      add(spr[p2++].second, -1);
    }
    int cnt = 0;
    for (int j = p2; j < p1; j++)
    {
      int d = abs(spr[j].second - it.second);
      if (d <= r)
      {
        cnt++;
      }
    }
    //assert(cnt == get(it.second + r) - get(it.second - r - 1));
    sol += (get(it.second + r) - get(it.second - r - 1) >= need);
  }
  cout << sol << "\n";
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 10
• Subtask 3: 18 / 18
• Subtask 4: 0 / 23
• Subtask 5: 0 / 19
• Subtask 6: 0 / 21