test/geometry/Counter_Clockwise.test.cpp

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Last update: 2023-06-08 15:34:10+09:00
Problem: https://onlinejudge.u-aizu.ac.jp/courses/library/4/CGL/1/CGL_1_C

Depends on

Code

#define PROBLEM \
    "https://onlinejudge.u-aizu.ac.jp/courses/library/4/CGL/1/CGL_1_C"

#include "../../geometry/base_ld.hpp"
#include "../../template/template.hpp"

using namespace lib;

int main() {
    std::cout << std::fixed << std::setprecision(15);
    long double x1, y1, x2, y2;
    std::cin >> x1 >> y1 >> x2 >> y2;
    vec p0(x1, y1), p1(x2, y2);
    int q;
    std::cin >> q;
    while (q--) {
        double x, y;
        std::cin >> x >> y;
        int flag = isp(p0, p1, vec(x, y));
        std::string ans;
        if (flag == 1) {
            ans = "COUNTER_CLOCKWISE";
        } else if (flag == -1) {
            ans = "CLOCKWISE";
        } else if (flag == -2) {
            ans = "ONLINE_BACK";
        } else if (flag == 2) {
            ans = "ONLINE_FRONT";
        } else {
            ans = "ON_SEGMENT";
        }
        std::cout << ans << std::endl;
    }
}

#line 1 "test/geometry/Counter_Clockwise.test.cpp"
#define PROBLEM \
    "https://onlinejudge.u-aizu.ac.jp/courses/library/4/CGL/1/CGL_1_C"

#line 2 "geometry/base_ld.hpp"

#line 2 "template/template.hpp"

#include <bits/stdc++.h>

#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
#define all(v) v.begin(), v.end()

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template <typename T> bool chmin(T &a, const T &b) {
    if (a <= b) return false;
    a = b;
    return true;
}
template <typename T> bool chmax(T &a, const T &b) {
    if (a >= b) return false;
    a = b;
    return true;
}

namespace lib {

using namespace std;

}  // namespace lib

// using namespace lib;
#line 4 "geometry/base_ld.hpp"

namespace lib {

using vec = complex<ld>;

const ld PI = acos(-1);

void ldout(int len = 20) {
    cout << fixed << setprecision(len);
}

int sgn(ld a, const ld eps = 1e-7) {
    return (a < -eps) ? -1 : (a > eps) ? 1 : 0;
}

bool same_vec(vec a, vec b) {
    a -= b;
    return sgn(a.real()) == 0 && sgn(a.imag()) == 0;
}

ld dot(const vec &a, const vec &b) {
    return (conj(a) * b).real();
}

ld cross(const vec &a, const vec &b) {
    return (conj(a) * b).imag();
}

int isp(const vec &a, const vec &b, const vec &c) {
    int cross_sgn = sgn(cross(b - a, c - a));
    if (cross_sgn == 0) {
        if (sgn(dot(b - a, c - a)) < 0) return -2;
        if (sgn(dot(a - b, c - b)) < 0) return 2;
    }
    return cross_sgn;
}

vec rot90(const vec &a) {
    return {-a.imag(), a.real()};
}

vec rot(const vec &a, ld rad) {
    return a * vec(cosl(rad), sinl(rad));
}

bool comp_for_argument_sort(const vec &lhs, const vec &rhs) {
    // if (abs(arg(lhs)-arg(rhs)) < eps) return false; // need ?
    return arg(lhs) < arg(rhs);
}

}  // namespace lib
#line 6 "test/geometry/Counter_Clockwise.test.cpp"

using namespace lib;

int main() {
    std::cout << std::fixed << std::setprecision(15);
    long double x1, y1, x2, y2;
    std::cin >> x1 >> y1 >> x2 >> y2;
    vec p0(x1, y1), p1(x2, y2);
    int q;
    std::cin >> q;
    while (q--) {
        double x, y;
        std::cin >> x >> y;
        int flag = isp(p0, p1, vec(x, y));
        std::string ans;
        if (flag == 1) {
            ans = "COUNTER_CLOCKWISE";
        } else if (flag == -1) {
            ans = "CLOCKWISE";
        } else if (flag == -2) {
            ans = "ONLINE_BACK";
        } else if (flag == 2) {
            ans = "ONLINE_FRONT";
        } else {
            ans = "ON_SEGMENT";
        }
        std::cout << ans << std::endl;
    }
}