Submission #548727

#	Time	Username	Problem	Language	Result	Execution time	Memory
548727		usukhbaatar	Collecting Mushrooms (NOI18_collectmushrooms)	C++14	100 / 100	113 ms	17920 KiB

mushrooms

#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;

int H, W, D, K;
vector<pair<pair<int, int>, pair<int, int>>> v;

int bit[2000001];

int N;

int query(int i) {
	int ii = i;
	int res = 0;
	while (i > 0) {
		res += bit[i];
		i -= (i & -i);
	}
	//cout << "query: " << ii << ": " << res << endl;
	return res;
}

void update(int i, int x) {
	while (i <= N) {
		bit[i] += x;
		i += (i & -i);
	}
}

void update(int l, int r, int x) {
	//cout << "update: " << l << " " << r << " " << x << endl;
	update(l, x);
	update(r + 1, -x);
}

int main() {
	cin >> H >> W >> D >> K;
	N = W + 2 * D;
	string temp;

	for (int i = 0; i < H; i++) {
		cin >> temp;
		for (int j = 0; j < W; j++) {
			if (temp[j] == 'M') {
				v.push_back({{i, 2}, {j + D + 1, j + D + 1}});
			}
			if (temp[j] == 'S') {
				v.push_back({{i - D, 1}, {j + 1, j + 2 * D + 1}});
				v.push_back({{i + D, 3}, {j + 1, j + 2 * D + 1}});
			}
		}
	}

	sort(v.begin(), v.end());
	int ans = 0;
	for (int i = 0; i < v.size(); i++) {
		if (v[i].first.second == 2) {
			int temp = query(v[i].second.first);
			//cout << temp << endl;
			if (temp >= K) {
				ans++;
			}
		} else {
			update(v[i].second.first, v[i].second.second, v[i].first.second == 3 ? -1 : 1);
		}
	}
	cout << ans << endl;
	return 0;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int query(int)':
mushrooms.cpp:15:6: warning: unused variable 'ii' [-Wunused-variable]
   15 |  int ii = i;
      |      ^~
mushrooms.cpp: In function 'int main()':
mushrooms.cpp:58:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<int, int>, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |  for (int i = 0; i < v.size(); i++) {
      |                  ~~^~~~~~~~~~

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