結果

問題 No.947 ABC包囲網
コンテスト
ユーザー hitonanode
提出日時 2019-12-10 00:47:27
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 1,045 ms / 2,000 ms
コード長 4,720 bytes
コンパイル時間 2,027 ms
コンパイル使用メモリ 176,652 KB
実行使用メモリ 5,376 KB
最終ジャッジ日時 2024-06-23 10:45:59
合計ジャッジ時間 26,606 ms
ジャッジサーバーID
（参考情報） 		judge5 / 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
other AC * 60
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((lint)(x).size())
#define POW2(n) (1LL << (n))
#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> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
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> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
///// This part below is only for debug, not used /////
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
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> ostream &operator<<(ostream &os, const unordered_set<T> &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> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;
///// END /////
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/tag_and_trait.hpp>
using namespace __gnu_pbds; // find_by_order(), order_of_key()
template<typename TK> using pbds_set = tree<TK, null_type, less<TK>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename TK, typename TV> using pbds_map = tree<TK, TV, less<TK>, rb_tree_tag, tree_order_statistics_node_update>;
*/

constexpr double eps = 1e-2;
struct P
{
    double theta;
    lint X, Y;
    bool operator<(const P &r) const {
        double b = theta - r.theta;
        if (abs(b) > eps) return b < 0;
        return X * r.Y - r.X * Y > 0;
    }
    bool operator==(const P &r) const {
        return X * r.Y == r.X * Y;
    }
    void rotate_pi() {
        theta += M_PI;
        X *= -1;
        Y *= -1;
    }
};

int main()
{
    int N;
    cin >> N;
    vector<P> p;
    REP(i, N) {
        lint x, y;
        cin >> x >> y;
        if (x == 0 and y == 0) continue;
        p.resize(p.size() + 1);
        p.back().X = x, p.back().Y = y;
    }
    N = p.size();
    REP(i, N) p[i].theta = atan2(p[i].Y, p[i].X);
    sort(ALL(p));

    REP(i, N * 4)
    {
        p.emplace_back(p[i]);
        p.back().theta += 2 * M_PI;
    }
    lint ret = 0;
    REP(i, N) REP(j, i) {
        P a = p[i], b = p[j];
        if (a == b) continue;
        if (b < a) swap(a, b);
        if (b.theta - a.theta > M_PI) a.theta += M_PI * 2, swap(a, b);
        a.rotate_pi();
        if (a == b) continue;
        b.rotate_pi();
        int ad = lower_bound(ALL(p), b) - upper_bound(ALL(p), a);
        ret += ad;
    }
    cout << ret / 3 << endl;
}
0