結果
問題 | No.2173 Nightcord |
ユーザー | hitonanode |
提出日時 | 2023-01-03 08:07:39 |
言語 | C++23 (gcc 12.3.0 + boost 1.83.0) |
結果 |
WA
|
実行時間 | - |
コード長 | 20,324 bytes |
コンパイル時間 | 2,891 ms |
コンパイル使用メモリ | 219,720 KB |
実行使用メモリ | 5,376 KB |
最終ジャッジ日時 | 2024-05-05 07:02:44 |
合計ジャッジ時間 | 49,721 ms |
ジャッジサーバーID (参考情報) |
judge4 / judge2 |
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テストケース
テストケース表示入力 | 結果 | 実行時間 実行使用メモリ |
---|---|---|
testcase_00 | AC | 2 ms
5,248 KB |
testcase_01 | AC | 2 ms
5,376 KB |
testcase_02 | AC | 2 ms
5,376 KB |
testcase_03 | AC | 1,699 ms
5,376 KB |
testcase_04 | AC | 4 ms
5,376 KB |
testcase_05 | AC | 1,151 ms
5,376 KB |
testcase_06 | AC | 164 ms
5,376 KB |
testcase_07 | AC | 311 ms
5,376 KB |
testcase_08 | AC | 1,792 ms
5,376 KB |
testcase_09 | WA | - |
testcase_10 | AC | 556 ms
5,376 KB |
testcase_11 | WA | - |
testcase_12 | AC | 1,110 ms
5,376 KB |
testcase_13 | WA | - |
testcase_14 | WA | - |
testcase_15 | AC | 1,159 ms
5,376 KB |
testcase_16 | AC | 2,203 ms
5,376 KB |
testcase_17 | WA | - |
testcase_18 | AC | 632 ms
5,376 KB |
testcase_19 | WA | - |
testcase_20 | AC | 681 ms
5,376 KB |
testcase_21 | WA | - |
testcase_22 | WA | - |
testcase_23 | AC | 1,008 ms
5,376 KB |
testcase_24 | WA | - |
testcase_25 | AC | 1,421 ms
5,376 KB |
testcase_26 | WA | - |
testcase_27 | WA | - |
testcase_28 | AC | 1,595 ms
5,376 KB |
testcase_29 | WA | - |
testcase_30 | AC | 1,880 ms
5,376 KB |
testcase_31 | WA | - |
testcase_32 | AC | 201 ms
5,376 KB |
testcase_33 | AC | 1,594 ms
5,376 KB |
testcase_34 | AC | 2,080 ms
5,376 KB |
testcase_35 | AC | 988 ms
5,376 KB |
testcase_36 | AC | 1,255 ms
5,376 KB |
testcase_37 | AC | 1,724 ms
5,376 KB |
testcase_38 | AC | 1,307 ms
5,376 KB |
testcase_39 | AC | 173 ms
5,376 KB |
testcase_40 | AC | 2,036 ms
5,376 KB |
testcase_41 | AC | 1,334 ms
5,376 KB |
testcase_42 | AC | 1,479 ms
5,376 KB |
testcase_43 | AC | 95 ms
5,376 KB |
testcase_44 | AC | 4 ms
5,376 KB |
testcase_45 | AC | 357 ms
5,376 KB |
testcase_46 | AC | 1,265 ms
5,376 KB |
testcase_47 | AC | 484 ms
5,376 KB |
testcase_48 | AC | 385 ms
5,376 KB |
testcase_49 | AC | 10 ms
5,376 KB |
testcase_50 | AC | 104 ms
5,376 KB |
testcase_51 | AC | 533 ms
5,376 KB |
testcase_52 | AC | 7 ms
5,376 KB |
testcase_53 | AC | 541 ms
5,376 KB |
testcase_54 | AC | 898 ms
5,376 KB |
testcase_55 | AC | 160 ms
5,376 KB |
testcase_56 | AC | 359 ms
5,376 KB |
ソースコード
#include <algorithm> #include <array> #include <bitset> #include <cassert> #include <chrono> #include <cmath> #include <complex> #include <deque> #include <forward_list> #include <fstream> #include <functional> #include <iomanip> #include <ios> #include <iostream> #include <limits> #include <list> #include <map> #include <numeric> #include <queue> #include <random> #include <set> #include <sstream> #include <stack> #include <string> #include <tuple> #include <type_traits> #include <unordered_map> #include <unordered_set> #include <utility> #include <vector> using namespace std; using lint = long long; using pint = pair<int, int>; using plint = pair<lint, lint>; struct fast_ios { fast_ios(){ cin.tie(nullptr), ios::sync_with_stdio(false), cout << fixed << setprecision(20); }; } fast_ios_; #define ALL(x) (x).begin(), (x).end() #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++) #define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template <typename T, typename V> void ndarray(vector<T>& vec, const V& val, int len) { vec.assign(len, val); } template <typename T, typename V, typename... Args> void ndarray(vector<T>& vec, const V& val, int len, Args... args) { vec.resize(len), for_each(begin(vec), end(vec), [&](T& v) { ndarray(v, val, args...); }); } template <typename T> bool chmax(T &m, const T q) { return m < q ? (m = q, true) : false; } template <typename T> bool chmin(T &m, const T q) { return m > q ? (m = q, true) : false; } const std::vector<std::pair<int, int>> grid_dxs{{1, 0}, {-1, 0}, {0, 1}, {0, -1}}; int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); } template <class T1, class T2> T1 floor_div(T1 num, T2 den) { return (num > 0 ? num / den : -((-num + den - 1) / den)); } template <class T1, class T2> std::pair<T1, T2> operator+(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first + r.first, l.second + r.second); } template <class T1, class T2> std::pair<T1, T2> operator-(const std::pair<T1, T2> &l, const std::pair<T1, T2> &r) { return std::make_pair(l.first - r.first, l.second - r.second); } template <class T> std::vector<T> sort_unique(std::vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); return vec; } template <class T> int arglb(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::lower_bound(v.begin(), v.end(), x)); } template <class T> int argub(const std::vector<T> &v, const T &x) { return std::distance(v.begin(), std::upper_bound(v.begin(), v.end(), x)); } template <class IStream, class T> IStream &operator>>(IStream &is, std::vector<T> &vec) { for (auto &v : vec) is >> v; return is; } template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec); template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr); template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec); template <class OStream, class T, class U> OStream &operator<<(OStream &os, const pair<T, U> &pa); template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec); template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec); template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec); template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec); template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa); template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp); template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp); template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl); template <class OStream, class T> OStream &operator<<(OStream &os, const std::vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; } template <class OStream, class T, size_t sz> OStream &operator<<(OStream &os, const std::array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; return os; } template <class... T> std::istream &operator>>(std::istream &is, std::tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return is; } template <class OStream, class... T> OStream &operator<<(OStream &os, const std::tuple<T...> &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << ','), ...);}, tpl); return os << ')'; } template <class OStream, class T, class TH> OStream &operator<<(OStream &os, const std::unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template <class OStream, class T> OStream &operator<<(OStream &os, const std::deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; } template <class OStream, class T> OStream &operator<<(OStream &os, const std::set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template <class OStream, class T> OStream &operator<<(OStream &os, const std::multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template <class OStream, class T> OStream &operator<<(OStream &os, const std::unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; } template <class OStream, class T, class U> OStream &operator<<(OStream &os, const std::pair<T, U> &pa) { return os << '(' << pa.first << ',' << pa.second << ')'; } template <class OStream, class TK, class TV> OStream &operator<<(OStream &os, const std::map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; } template <class OStream, class TK, class TV, class TH> OStream &operator<<(OStream &os, const std::unordered_map<TK, TV, TH> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v.second << ','; os << '}'; return os; } #ifdef HITONANODE_LOCAL const string COLOR_RESET = "\033[0m", BRIGHT_GREEN = "\033[1;32m", BRIGHT_RED = "\033[1;31m", BRIGHT_CYAN = "\033[1;36m", NORMAL_CROSSED = "\033[0;9;37m", RED_BACKGROUND = "\033[1;41m", NORMAL_FAINT = "\033[0;2m"; #define dbg(x) std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl #define dbgif(cond, x) ((cond) ? std::cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << std::endl : std::cerr) #else #define dbg(x) ((void)0) #define dbgif(cond, x) ((void)0) #endif #include <algorithm> #include <cassert> #include <cmath> #include <complex> #include <iostream> #include <tuple> #include <utility> #include <vector> template <typename T_P> struct Point2d { static T_P EPS; static void set_eps(T_P e) { EPS = e; } T_P x, y; Point2d() : x(0), y(0) {} Point2d(T_P x, T_P y) : x(x), y(y) {} Point2d(const std::pair<T_P, T_P> &p) : x(p.first), y(p.second) {} Point2d(const std::complex<T_P> &p) : x(p.real()), y(p.imag()) {} std::complex<T_P> to_complex() const noexcept { return {x, y}; } Point2d operator+(const Point2d &p) const noexcept { return Point2d(x + p.x, y + p.y); } Point2d operator-(const Point2d &p) const noexcept { return Point2d(x - p.x, y - p.y); } Point2d operator*(const Point2d &p) const noexcept { static_assert(std::is_floating_point<T_P>::value == true); return Point2d(x * p.x - y * p.y, x * p.y + y * p.x); } Point2d operator*(T_P d) const noexcept { return Point2d(x * d, y * d); } Point2d operator/(T_P d) const noexcept { static_assert(std::is_floating_point<T_P>::value == true); return Point2d(x / d, y / d); } Point2d inv() const { static_assert(std::is_floating_point<T_P>::value == true); return conj() / norm2(); } Point2d operator/(const Point2d &p) const { return (*this) * p.inv(); } bool operator<(const Point2d &r) const noexcept { return x != r.x ? x < r.x : y < r.y; } bool operator==(const Point2d &r) const noexcept { return x == r.x and y == r.y; } bool operator!=(const Point2d &r) const noexcept { return !((*this) == r); } T_P dot(Point2d p) const noexcept { return x * p.x + y * p.y; } T_P det(Point2d p) const noexcept { return x * p.y - y * p.x; } T_P absdet(Point2d p) const noexcept { return std::abs(det(p)); } T_P norm() const noexcept { static_assert(std::is_floating_point<T_P>::value == true); return std::sqrt(x * x + y * y); } T_P norm2() const noexcept { return x * x + y * y; } T_P arg() const noexcept { return std::atan2(y, x); } // rotate point/vector by rad Point2d rotate(T_P rad) const noexcept { static_assert(std::is_floating_point<T_P>::value == true); return Point2d(x * std::cos(rad) - y * std::sin(rad), x * std::sin(rad) + y * std::cos(rad)); } Point2d normalized() const { static_assert(std::is_floating_point<T_P>::value == true); return (*this) / this->norm(); } Point2d conj() const noexcept { return Point2d(x, -y); } template <class IStream> friend IStream &operator>>(IStream &is, Point2d &p) { T_P x, y; is >> x >> y; p = Point2d(x, y); return is; } template <class OStream> friend OStream &operator<<(OStream &os, const Point2d &p) { return os << '(' << p.x << ',' << p.y << ')'; } }; template <> double Point2d<double>::EPS = 1e-9; template <> long double Point2d<long double>::EPS = 1e-12; template <> long long Point2d<long long>::EPS = 0; template <typename T_P> int ccw(const Point2d<T_P> &a, const Point2d<T_P> &b, const Point2d<T_P> &c) { // a->b->cの曲がり方 Point2d<T_P> v1 = b - a; Point2d<T_P> v2 = c - a; if (v1.det(v2) > Point2d<T_P>::EPS) return 1; // 左折 if (v1.det(v2) < -Point2d<T_P>::EPS) return -1; // 右折 if (v1.dot(v2) < -Point2d<T_P>::EPS) return 2; // c-a-b if (v1.norm2() < v2.norm2()) return -2; // a-b-c return 0; // a-c-b } // Convex hull (凸包) // return: IDs of vertices used for convex hull, counterclockwise // include_boundary: If true, interior angle pi is allowed template <typename T_P> std::vector<int> convex_hull(const std::vector<Point2d<T_P>> &ps, bool include_boundary = false) { int n = ps.size(); if (n <= 1) return std::vector<int>(n, 0); std::vector<std::pair<Point2d<T_P>, int>> points(n); for (size_t i = 0; i < ps.size(); i++) points[i] = std::make_pair(ps[i], i); std::sort(points.begin(), points.end()); int k = 0; std::vector<std::pair<Point2d<T_P>, int>> qs(2 * n); auto ccw_check = [&](int c) { return include_boundary ? (c == -1) : (c <= 0); }; for (int i = 0; i < n; i++) { while (k > 1 and ccw_check(ccw(qs[k - 2].first, qs[k - 1].first, points[i].first))) k--; qs[k++] = points[i]; } for (int i = n - 2, t = k; i >= 0; i--) { while (k > t and ccw_check(ccw(qs[k - 2].first, qs[k - 1].first, points[i].first))) k--; qs[k++] = points[i]; } std::vector<int> ret(k - 1); for (int i = 0; i < k - 1; i++) ret[i] = qs[i].second; return ret; } // Solve r1 + t1 * v1 == r2 + t2 * v2 template <typename T_P, typename std::enable_if<std::is_floating_point<T_P>::value>::type * = nullptr> Point2d<T_P> lines_crosspoint(Point2d<T_P> r1, Point2d<T_P> v1, Point2d<T_P> r2, Point2d<T_P> v2) { static_assert(std::is_floating_point<T_P>::value == true); assert(v2.det(v1) != 0); return r1 + v1 * (v2.det(r2 - r1) / v2.det(v1)); } // Whether two segments s1t1 & s2t2 intersect or not (endpoints not included) // Google Code Jam 2013 Round 3 - Rural Planning // Google Code Jam 2021 Round 3 - Fence Design template <typename T> bool intersect_open_segments(Point2d<T> s1, Point2d<T> t1, Point2d<T> s2, Point2d<T> t2) { if (s1 == t1 or s2 == t2) return false; // Not segment but point int nbad = 0; for (int t = 0; t < 2; t++) { Point2d<T> v1 = t1 - s1, v2 = t2 - s2; T den = v2.det(v1); if (den == 0) { if (s1.det(v1) == s2.det(v1)) { auto L1 = s1.dot(v1), R1 = t1.dot(v1); auto L2 = s2.dot(v1), R2 = t2.dot(v1); if (L1 > R1) std::swap(L1, R1); if (L2 > R2) std::swap(L2, R2); if (L1 > L2) std::swap(L1, L2), std::swap(R1, R2); return R1 > L2; } else { return false; } } else { auto num = v2.det(s2 - s1); if ((0 < num and num < den) or (den < num and num < 0)) nbad++; } std::swap(s1, s2); std::swap(t1, t2); } return nbad == 2; } // Whether point p is on segment (s, t) (endpoints not included) // Google Code Jam 2013 Round 3 - Rural Planning template <typename PointNd> bool is_point_on_open_segment(PointNd s, PointNd t, PointNd p) { if (s == t) return false; // not segment but point if (p == s or p == t) return false; auto v = t - s, w = p - s; if (v.absdet(w)) return false; auto vv = v.dot(v), vw = v.dot(w); return vw > 0 and vw < vv; } // Convex cut // Cut the convex polygon g by line p1->p2 and return the leftward one template <typename T_P> std::vector<Point2d<T_P>> convex_cut(const std::vector<Point2d<T_P>> &g, Point2d<T_P> p1, Point2d<T_P> p2) { static_assert(std::is_floating_point<T_P>::value == true); assert(p1 != p2); std::vector<Point2d<T_P>> ret; for (int i = 0; i < (int)g.size(); i++) { const Point2d<T_P> &now = g[i], &nxt = g[(i + 1) % g.size()]; if (ccw(p1, p2, now) != -1) ret.push_back(now); if ((ccw(p1, p2, now) == -1) xor (ccw(p1, p2, nxt) == -1)) { ret.push_back(lines_crosspoint(now, nxt - now, p1, p2 - p1)); } } return ret; } // 2円の交点 (ABC157F, SRM 559 Div.1 900) template <typename T_P> std::vector<Point2d<T_P>> IntersectTwoCircles(const Point2d<T_P> &Ca, T_P Ra, const Point2d<T_P> &Cb, T_P Rb) { static_assert(std::is_floating_point<T_P>::value == true); T_P d = (Ca - Cb).norm(); if (Ra + Rb < d) return {}; T_P rc = (d * d + Ra * Ra - Rb * Rb) / (2 * d); T_P rs2 = Ra * Ra - rc * rc; if (rs2 < 0) return {}; T_P rs = std::sqrt(rs2); Point2d<T_P> diff = (Cb - Ca) / d; return {Ca + diff * Point2d<T_P>(rc, rs), Ca + diff * Point2d<T_P>(rc, -rs)}; } // Solve |x0 + vt| = R (SRM 543 Div.1 1000, GCJ 2016 R3 C) template <typename PointNd, typename Float> std::vector<Float> IntersectCircleLine(const PointNd &x0, const PointNd &v, Float R) { static_assert(std::is_floating_point<Float>::value == true); Float b = Float(x0.dot(v)) / v.norm2(); Float c = Float(x0.norm2() - Float(R) * R) / v.norm2(); if (b * b - c < 0) return {}; Float ret1 = -b + sqrtl(b * b - c) * (b > 0 ? -1 : 1); Float ret2 = c / ret1; return ret1 < ret2 ? std::vector<Float>{ret1, ret2} : std::vector<Float>{ret2, ret1}; } // Distance between point p <-> line ab template <typename PointFloat> decltype(PointFloat::x) DistancePointLine(const PointFloat &p, const PointFloat &a, const PointFloat &b) { assert(a != b); return (b - a).absdet(p - a) / (b - a).norm(); } // Distance between point p <-> line segment ab template <typename PointFloat> decltype(PointFloat::x) DistancePointSegment(const PointFloat &p, const PointFloat &a, const PointFloat &b) { if (a == b) { return (p - a).norm(); } else if ((p - a).dot(b - a) <= 0) { return (p - a).norm(); } else if ((p - b).dot(a - b) <= 0) { return (p - b).norm(); } else { return DistancePointLine<PointFloat>(p, a, b); } } // Area of polygon (might be negative) template <typename T_P> T_P signed_area_of_polygon(const std::vector<Point2d<T_P>> &poly) { static_assert(std::is_floating_point<T_P>::value == true); T_P area = 0; for (size_t i = 0; i < poly.size(); i++) area += poly[i].det(poly[(i + 1) % poly.size()]); return area * 0.5; } using Pt = Point2d<lint>; void Yes() { puts("Yes"); exit(0); } // Point on grid, sortable by its argument struct Point { constexpr static double eps = 1e-2; long long X, Y; double theta; Point() = default; Point(long long x, long long y) : X(x), Y(y), theta(std::atan2(y, x)) {} bool operator<(const Point &r) const { double b = theta - r.theta; return std::abs(b) > eps ? (b < 0) : (X * r.Y > r.X * Y); } bool operator==(const Point &r) const { return std::abs(theta - r.theta) < eps and X * r.Y == r.X * Y; } bool operator!=(const Point &r) const { return !(*this == r); } void rotate_pi() { theta += M_PI; X *= -1; Y *= -1; } }; // Key class must be comparable // Example: [(2, 3), (1, 5), (2, 2), (2, 3), (1, 4)] -> [(1, [5, 4]), (2, [3, 2, 3])] // Verified: https://atcoder.jp/contests/abc259/tasks/abc259_h template <class Key, class Value> std::vector<std::pair<Key, std::vector<Value>>> groupby(std::vector<std::pair<Key, Value>> xs) { using KV = std::pair<Key, Value>; std::stable_sort( xs.begin(), xs.end(), [&](const KV &l, const KV &r) { return l.first < r.first; }); std::vector<std::pair<Key, std::vector<Value>>> ret; for (const auto &x : xs) { if (ret.empty() or ret.back().first != x.first) { ret.emplace_back(x.first, std::vector<Value>()); } ret.back().second.push_back(x.second); } return ret; } int main() { int N, K; cin >> N >> K; vector<vector<Pt>> vs(2); vector<vector<Point2d<double>>> vfs; REP(i, N) { int x, y, c; cin >> x >> y >> c; vs.at(c - 1).emplace_back(x, y); } REP(_, 2) { for (const Pt &p : vs.front()) { vector<pair<Point, pair<bool, lint>>> as; for (const Pt &q : vs.front()) { if (p == q) continue; auto dx = q - p; as.emplace_back(Point(dx.x, dx.y), make_pair(false, dx.norm2())); } for (const Pt &q : vs.back()) { auto dx = q - p; as.emplace_back(Point(dx.x, dx.y), make_pair(true, dx.norm2())); } for (const auto &[key, vals] : groupby(as)) { lint min1 = ((1LL << 62) - 1) * 2 , max0 = -1; for (auto [flg, norm2] : vals) { if (flg) { chmin(min1, norm2); } else { chmax(max0, norm2); } } if (min1 < max0) Yes(); } } swap(vs.front(), vs.back()); } for (auto &v : vs) { vector<Pt> w; vector<Point2d<double>> wf; for (int i : convex_hull(v)) { w.push_back(v.at(i)); wf.push_back(Point2d<double>(v.at(i).x, v.at(i).y)); } v = w; vfs.push_back(wf); } dbg(vs); if (K > 3 and vs.front().size() and vs.back().size()) { REP(_, 2) { for (const auto &p : vs.back()) { Point2d<double> pf(p.x, p.y); double rot = 0; REP(i, vs.front().size()) { rot += ((vfs.front().at((i + 1) % vfs.front().size()) - pf) / (vfs.front().at(i) - pf)).arg(); } if (abs(rot) < 0.1) Yes(); } Pt flast = vs.front().back(); for (const auto &f : vs.front()) { Pt blast = vs.back().back(); for (const auto &b : vs.back()) { if (intersect_open_segments(flast, blast, f, b)) Yes(); blast = b; } flast = f; } swap(vs.front(), vs.back()); swap(vfs.front(), vfs.back()); } } puts("No"); }