結果

問題 No.2012 Largest Triangle
ユーザー hitonanode
提出日時 2022-07-15 22:20:24
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 181 ms / 2,500 ms
コード長 14,400 bytes
コンパイル時間 2,371 ms
コンパイル使用メモリ 195,492 KB
実行使用メモリ 20,588 KB
最終ジャッジ日時 2024-06-27 21:19:25
合計ジャッジ時間 7,024 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 1
other AC * 41
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ソースコード

diff #
プレゼンテーションモードにする

#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; }
int floor_lg(long long x) { return x <= 0 ? -1 : 63 - __builtin_clzll(x); }
template <typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l
    .second + r.second); }
template <typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l
    .second - r.second); }
template <typename T> vector<T> sort_unique(vector<T> vec) { sort(vec.begin(), vec.end()), vec.erase(unique(vec.begin(), vec.end()), vec.end()); 
    return vec; }
template <typename 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 <typename 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 <typename T> istream &operator>>(istream &is, vector<T> &vec) { for (auto &v : vec) is >> v; return is; }
template <typename T> ostream &operator<<(ostream &os, const vector<T> &vec) { os << '['; for (auto v : vec) os << v << ','; os << ']'; return os; }
template <typename T, size_t sz> ostream &operator<<(ostream &os, const array<T, sz> &arr) { os << '['; for (auto v : arr) os << v << ','; os << ']'; 
    return os; }
#if __cplusplus >= 201703L
template <typename... T> istream &operator>>(istream &is, tuple<T...> &tpl) { std::apply([&is](auto &&... args) { ((is >> args), ...);}, tpl); return 
    is; }
template <typename... T> ostream &operator<<(ostream &os, const tuple<T...> &tpl) { os << '('; std::apply([&os](auto &&... args) { ((os << args << '
    ,'), ...);}, tpl); return os << ')'; }
#endif
template <typename T> ostream &operator<<(ostream &os, const deque<T> &vec) { os << "deq["; for (auto v : vec) os << v << ','; os << ']'; return os; 
    }
template <typename T> ostream &operator<<(ostream &os, const set<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; }
template <typename T, typename TH> ostream &operator<<(ostream &os, const unordered_set<T, TH> &vec) { os << '{'; for (auto v : vec) os << v << ','; 
    os << '}'; return os; }
template <typename T> ostream &operator<<(ostream &os, const multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; return os; 
    }
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec) { os << '{'; for (auto v : vec) os << v << ','; os << '}'; 
    return os; }
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa) { os << '(' << pa.first << ',' << pa.second << ')'; 
    return os; }
template <typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp) { os << '{'; for (auto v : mp) os << v.first << "=>" << v
    .second << ','; os << '}'; return os; }
template <typename TK, typename TV, typename TH> ostream &operator<<(ostream &os, const 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) cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << COLOR_RESET << 
    endl
#define dbgif(cond, x) ((cond) ? cerr << BRIGHT_CYAN << #x << COLOR_RESET << " = " << (x) << NORMAL_FAINT << " (L" << __LINE__ << ") " << __FILE__ << 
    COLOR_RESET << endl : cerr)
#else
#define dbg(x) 0
#define dbgif(cond, x) 0
#endif
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)); }
    double 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; }
    double 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;
}
// Rational number + {infinity(1 / 0), -infiity(-1 / 0)} （有理数）
struct Rational {
    using Int = long long int; // __int128
    Int num, den;
    static Int my_gcd(Int a, Int b) {
        // // return __gcd(a, b);
        // if (a < 0) a = -a;
        // if (b < 0) b = -b;
        // while (a and b) {
        //     if (a > b)
        //         a %= b;
        //     else
        //         b %= a;
        // }
        // return a + b;
        return 1;
    }
    Rational(Int num = 0, Int den = 1) : num(num), den(den) { normalize(); }
    void normalize() { // reduction and making denominator nonnegative
        Int g = my_gcd(num, den);
        num /= g, den /= g;
        if (den < 0) num = -num, den = -den;
    }
    Rational operator+(const Rational &r) const {
        return Rational(num * r.den + den * r.num, den * r.den);
    }
    Rational operator-(const Rational &r) const {
        return Rational(num * r.den - den * r.num, den * r.den);
    }
    Rational operator*(const Rational &r) const { return Rational(num * r.num, den * r.den); }
    Rational operator/(const Rational &r) const { return Rational(num * r.den, den * r.num); }
    Rational &operator+=(const Rational &r) { return *this = *this + r; }
    Rational &operator-=(const Rational &r) { return *this = *this - r; }
    Rational &operator*=(const Rational &r) { return *this = *this * r; }
    Rational &operator/=(const Rational &r) { return *this = *this / r; }
    Rational operator-() const { return Rational(-num, den); }
    Rational abs() const { return Rational(num > 0 ? num : -num, den); }
    bool operator==(const Rational &r) const { return num == r.num and den == r.den; }
    bool operator!=(const Rational &r) const { return num != r.num or den != r.den; }
    bool operator<(const Rational &r) const {
        if (den == 0 and r.den == 0)
            return num < r.num;
        else if (den == 0)
            return num < 0;
        else if (r.den == 0)
            return r.num > 0;
        else
            return num * r.den < den * r.num;
    }
    bool operator<=(const Rational &r) const { return (*this == r) or (*this < r); }
    bool operator>(const Rational &r) const { return r < *this; }
    bool operator>=(const Rational &r) const { return (r == *this) or (r < *this); }
    explicit operator double() const { return (double)num / (double)den; }
    explicit operator long double() const { return (long double)num / (long double)den; }
    friend std::ostream &operator<<(std::ostream &os, const Rational &x) {
        return os << x.num << '/' << x.den;
    }
};
using Float = lint;
using Pt = Point2d<Float>;
// 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;
    }
    void rotate_pi() {
        theta += M_PI;
        X *= -1;
        Y *= -1;
    }
};
int main() {
    int N;
    cin >> N;
    vector<Pt> X;
    REP(i, N) {
        int x, y;
        cin >> x >> y;
        X.push_back(Pt(x, y));
    }
    vector<int> chid = convex_hull(X, true);
    vector<Pt> ch;
    for (auto i : chid) ch.push_back(X[i]);
    // vector<Rational> rads;
    vector<double> rads;
    vector<Point> radps;
    REP(i, ch.size()) {
        auto p = (ch[(i + 1) % ch.size()] - ch[i]);
        // rads.push_back(p.y, p.x);
        rads.push_back(p.arg());
        radps.push_back(Point(p.x, p.y));
    }
    int j = min_element(ALL(rads)) - rads.begin();
    rotate(ch.begin(), ch.begin() + j, ch.end());
    rotate(rads.begin(), rads.begin() + j, rads.end());
    rotate(radps.begin(), radps.begin() + j, radps.end());
    dbg(ch);
    dbg(rads);
    FOR(i, 1, radps.size()) assert(!(radps[i] < radps[i - 1]));
    dbg(ch);
    lint ret = 0;
    for (auto p : X) {
        const auto p0 = p;
        REP(t, 2) {
            // double r = p.arg();
            Point r(p.x, p.y);
            int i = arglb(radps, r);
            FOR(j, i - 1, i + 2) {
                Pt q = ch.at((j % ch.size() + ch.size()) % ch.size());
                lint h = q.det(p);
                if (chmax(ret, abs(h))) {
                    dbg(p);
                    dbg(q);
                }
            }
            p.x *= -1;
            p.y *= -1;
        }
    }
    cout << ret << '\n';
}
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