제출 #668258

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
668258		600Mihnea	Collecting Mushrooms (NOI18_collectmushrooms)	C++17	100 / 100	36 ms	7660 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 + 1});
        continue;
      }
      if (ch == 'M')
      {
        mus.push_back({i, j + 1});
        continue;
      }
      assert(0);
    }
  }
  vector<int> t(m + 1, 0);
  auto add = [&] (int i, int x)
  {
    while (i <= m)
    {
      t[i] += x;
      i += i & (-i);
    }
  };
  auto get = [&] (int i)
  {
    int sol = 0;
    while (i)
    {
      sol += t[i];
      i -= i & (-i);
    }
    return sol;
  };
  int sol = 0;
  sort(mus.begin(), mus.end());
  sort(spr.begin(), spr.end());
  int p1 = 0, p2 = 0;
  for (auto &it : mus)
  {
    while (p1 < (int) spr.size() && spr[p1].first <= it.first + r)
    {
      add(spr[p1].second, +1);
      p1++;
    }
    while (p2 < (int) spr.size() && spr[p2].first < it.first - r)
    {
      add(spr[p2].second, -1);
      p2++;
    }
    int low = max(1, it.second - r), high = min(m, it.second + r);
    sol += (get(high) - get(low - 1) >= need);
  }
  cout << sol << "\n";
}

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