103432024-03-31 20:51:39szilHázakcpp17Runtime error 30/100138ms44760 KiB
#include <bits/stdc++.h>

using namespace std;
using ll = long long;

struct Point {
	ll x, y;
};

struct Line {
	Point a, b;
	int idx;
};

struct Event {
	Point ord;
	Line line;
	bool add;
	int idx;
};

const int MAXN = 100'001;

bool ans[MAXN];

Point operator+(Point a, Point b) {
	return {a.x + b.x, a.y + b.y};
}

Point operator-(Point a, Point b) {
	return {a.x - b.x, a.y - b.y};
}

ll cross(Point a, Point b) {
	return a.x * b.y - a.y * b.x;
}

int forog(Point a, Point b, Point c) {
	ll x = cross(b - a, c - a);
	if (x > 0) return 1;
	if (x == 0) return 0;
	if (x < 0) return -1;
}

bool operator<(const Line &a, const Line &b) {
	if (cross(a.a, a.b)) {
		return forog(a.a, a.b, b.a) > 0 || forog(a.a, a.b, b.b) > 0;
	} else {
		return forog(a.b, a.a, b.a) > 0 || forog(a.b, a.a, b.b) > 0;
	}
}

int main() {
	ios::sync_with_stdio(0); cin.tie(0);
	int n; cin >> n;
	vector<Line> lines(n);
	vector<Event> events;
	for (Line &l : lines) {
		cin >> l.a.x >> l.b.y >> l.b.x >> l.a.y;
	}
	
	for (int i = 0; i < n; i++) {
		Event e1, e2;
		e1.line = e2.line = lines[i];
		e1.ord = lines[i].a;
		e2.ord = lines[i].b;
		e1.add = false;
		e2.add = true;
		e1.idx = e2.idx = i;
		events.emplace_back(e1);
		events.emplace_back(e2);
	}

	sort(events.begin(), events.end(), [&](auto a, auto b){
		ll forgas = cross(a.ord, b.ord);
		if (forgas == 0) {
			return a.ord.x*a.ord.x+a.ord.y*a.ord.y < b.ord.x*b.ord.x+b.ord.y*b.ord.y;
		}
		return forgas > 0;
	});

	set<Line> s;
	for (auto [ord, line, add, idx] : events) {
		line.idx = idx;
		if (add) {
			s.insert(line);
		} else {
			auto it = s.find(line);
			assert(it != s.end());
			s.erase(it);
		}
		if (!s.empty()) ans[s.begin()->idx] = true;
	}

	cout << count(ans, ans+MAXN, true) << "\n";
	for (int i = 0; i < n; i++) {
		if (ans[i]) cout << i+1 << " ";
	}
	cout << "\n";

	return 0;
}
SubtaskSumTestVerdictTimeMemory
subtask10/0
1Accepted3ms1832 KiB
2Accepted14ms7064 KiB
subtask215/15
3Accepted3ms2436 KiB
4Accepted4ms3044 KiB
5Accepted8ms5152 KiB
6Accepted14ms7880 KiB
7Accepted14ms8180 KiB
subtask315/15
8Accepted3ms3396 KiB
9Accepted3ms3716 KiB
10Accepted3ms3848 KiB
11Accepted3ms3876 KiB
12Accepted4ms4060 KiB
subtask40/20
13Accepted4ms4064 KiB
14Runtime error4ms4676 KiB
15Accepted8ms6256 KiB
16Accepted12ms6644 KiB
17Accepted12ms6824 KiB
subtask50/50
18Wrong answer28ms13904 KiB
19Accepted37ms14628 KiB
20Accepted68ms24592 KiB
21Accepted136ms44760 KiB
22Runtime error138ms44760 KiB