Submission #949972

#TimeUsernameProblemLanguageResultExecution timeMemory
949972vjudge1Printed Circuit Board (CEOI12_circuit)C++17
15 / 100
29 ms2908 KiB
#define _CRT_SECURE_NO_WARNINGS #include <iostream> #include <algorithm> #include <cmath> #include <cstring> #include <cassert> #include <vector> typedef long long ll; //typedef double ld; 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) {} bool operator == (const Pos& p) const { return x == p.x && y == p.y; } bool operator != (const Pos& p) const { return x != p.x || y != p.y; } 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 }; } bool operator < (const Pos& p) const { return *this / p > 0; } bool operator <= (const Pos& p) const { return *this / p >= 0; } 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> C, H; 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) { if (area(H) > 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);//normalization 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; if (fvis && bvis) { int CCW = ccw(H[(i - 1 + N) % N], H[i % N], H[(i + 1) % N]); if (H[i % N] / H[(i + 1) % N] < 0) {//move backward if (!rvs && CCW < 0) { rvs = 1; fvis = 0; continue; } rvs = 1; while (stack.size() && invisible(H[i % N], H[(i + 1) % N], H[stack.back() % N])) stack.pop_back(); } else if (H[i % N] / H[(i + 1) % N] == 0) {//move vertical if (H[i % N].Euc() > H[(i + 1) % N].Euc()) { //rvs = 0; if (stack[stack.size() - 1] == i) stack.pop_back(); if (stack.size() < 1 || H[stack.back() % N] / H[(i + 1) % N] > 0) stack.push_back(i + 1); } } else if (H[i % N] / H[(i + 1) % N] > 0) {//move forward if (rvs && CCW > 0) { stack.push_back(i); rvs = 0; bvis = 0; continue; } rvs = 0; if (stack.size() < 1 || H[stack.back() % N] / H[(i + 1) % N] > 0) stack.push_back(i + 1); } } else if (!fvis) { if (H[stack.back() % N] / H[(i + 1) % N] > 0) { rvs = 0; fvis = 1; stack.push_back(i + 1); } } else if (!bvis) { if (H[stack.back() % N] / H[(i + 1) % N] < 0) { stack.pop_back(); rvs = 1; bvis = 1; while (stack.size() && invisible(H[i % N], H[(i + 1) % N], H[stack.back() % N])) stack.pop_back(); } } } for (const int& i : stack) V[H[i % N].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
#Verdict Execution timeMemoryGrader output
Fetching results...