oj.uz

답안 #950056

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
950056 2024-03-20T04:31:21 Z vjudge1 Printed Circuit Board (CEOI12_circuit) C++17
60 / 100
 31 ms 2908 KB 
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <vector>
#include <cassert>
typedef long long ll;
const ll INF = 1e17;
const int LEN = 2e5 + 1;
int N;
bool V[LEN];

struct Pos {
	int x, y, i;
	Pos(int X = 0, int Y = 0, int I = 0) : x(X), y(Y), i(I) {}
	ll operator * (const Pos& p) const { return { (ll)x * p.x + (ll)y * p.y }; }
	ll operator / (const Pos& p) const { return { (ll)x * p.y - (ll)y * p.x }; }
	Pos operator + (const Pos& p) const { return { x + p.x, y + p.y }; }
	Pos operator - (const Pos& p) const { return { x - p.x, y - p.y }; }
	ll Euc() const { return (ll)x * x + (ll)y * y; }
	friend std::istream& operator >> (std::istream& is, Pos& p) {
		is >> p.x >> p.y;
		return is;
	}
	friend std::ostream& operator << (std::ostream& os, const Pos& p) {
		os << p.x << " " << p.y;
		return os;
	}
}; const Pos O = { 0, 0 };
std::vector<Pos> H;// , C;
ll cross(const Pos& d1, const Pos& d2, const Pos& d3) { return (d2 - d1) / (d3 - d2); }
int ccw(const Pos& d1, const Pos& d2, const Pos& d3) {
	ll ret = cross(d1, d2, d3);
	return !ret ? 0 : ret > 0 ? 1 : -1;
}
ll area(const std::vector<Pos>& H) {
	ll ret = 0;
	int sz = H.size();
	for (int i = 0; i < sz; i++) {
		Pos cur = H[i], nxt = H[(i + 1) % sz];
		ret += cross(O, cur, nxt);
	}
	return ret;
}
bool norm(std::vector<Pos>& H) {
	ll A = area(H);
	assert(A);
	if (A > 0) { std::reverse(H.begin(), H.end()); return 1; }
	return 0;
}
int invisible(const Pos& p1, const Pos& p2, const Pos& t) {
	if (p1 / t == 0 && p1.Euc() <= t.Euc()) return 1;
	if (p2 / t == 0 && p2.Euc() <= t.Euc()) return 1;
	return ccw(O, p1, t) < 0 && ccw(O, p2, t) > 0 && ccw(p1, p2, t) > 0;
}
std::vector<int> stack;
void solve() {
	std::cin.tie(0)->sync_with_stdio(0);
	std::cout.tie(0);
	memset(V, 0, sizeof V);
	std::cin >> N;
	H.resize(N);
	for (int i = 0; i < N; i++) std::cin >> H[i], H[i].i = i + 1;
	//norm(H);//normalize cw

	int r = 0, l = 0;
	ll LMIN = H[0].Euc(), RMIN = H[0].Euc();
	for (int i = 0; i < N; i++) {
		if (H[r] / H[i] < 0 ||
			(H[r] / H[i] == 0 && RMIN > H[i].Euc())) {
			r = i, RMIN = H[i].Euc();
		}
		if (H[l] / H[i] > 0 ||
			(H[l] / H[i] == 0 && LMIN > H[i].Euc())) {
			l = i, LMIN = H[i].Euc();
		}
	}

	stack.clear();
	stack.push_back(r);
	V[H[r].i] = 1;

	bool fvis = 1, bvis = 1, rvs = 0;
	for (int i = r; i < r + N; i++) {
		if (i % N == l) break;
		Pos& pre = H[(i - 1 + N) % N], cur = H[i % N], nxt = H[(i + 1) % N];
		if (fvis && bvis) {
			ll DIR = cur / nxt;
			int CCW = ccw(pre, cur, nxt);
			if (DIR < 0) {//move backward
				if (!rvs && CCW < 0) {
					rvs = 1;
					fvis = 0;
					continue;
				}
				rvs = 1;
				while (stack.size() && invisible(cur, nxt, H[stack.back()])) stack.pop_back();
			}
			else if (!DIR) {//move vertical
				if (cur.Euc() > nxt.Euc()) {
					if (stack.size() && stack.back() == i % N) stack.pop_back();
					if (stack.size() < 1 || H[stack.back()] / nxt > 0) stack.push_back((i + 1) % N);
				}
			}
			else if (DIR > 0) {//move forward
				if (rvs && CCW > 0) {
					stack.push_back(i % N);
					rvs = 0;
					bvis = 0;
					continue;
				}
				if (stack.size() && rvs && H[stack.back()] / cur > 0) stack.push_back(i % N);
				rvs = 0;
				if (stack.size() < 1 || H[stack.back()] / nxt > 0) stack.push_back((i + 1) % N);
			}
		}
		else if (!fvis) {
			if (H[stack.back()] / nxt > 0) {
				rvs = 0;
				fvis = 1;
				stack.push_back((i + 1) % N);
			}
		}
		else if (!bvis) {
			if (H[stack.back()] / nxt < 0) {
				stack.pop_back();
				rvs = 1;
				bvis = 1;
				while (stack.size() && invisible(cur, nxt, H[stack.back()])) stack.pop_back();
			}
		}
	}
	for (const int& i : stack) V[H[i].i] = 1;
	std::cout << stack.size() << "\n";
	for (int i = 1; i <= N; i++) if (V[i]) std::cout << i << " ";
	return;
}
int main() { solve(); return 0; }//boj3303 Printed Circuit Board

Subtask #1
60.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 600 KB Output is correct
2 Correct 1 ms 604 KB Output is correct
3 Incorrect 1 ms 604 KB Output isn't correct
4 Correct 1 ms 856 KB Output is correct
5 Correct 2 ms 604 KB Output is correct
6 Correct 2 ms 600 KB Output is correct
7 Correct 3 ms 860 KB Output is correct
8 Correct 2 ms 604 KB Output is correct
9 Incorrect 1 ms 604 KB Output isn't correct
10 Correct 2 ms 604 KB Output is correct
11 Correct 2 ms 604 KB Output is correct
12 Incorrect 3 ms 860 KB Output isn't correct
13 Correct 5 ms 860 KB Output is correct
14 Incorrect 5 ms 1116 KB Output isn't correct
15 Incorrect 6 ms 1116 KB Output isn't correct
16 Incorrect 14 ms 1624 KB Output isn't correct
17 Correct 14 ms 1628 KB Output is correct
18 Incorrect 26 ms 2908 KB Output isn't correct
19 Incorrect 31 ms 2908 KB Output isn't correct
20 Correct 30 ms 2908 KB Output is correct