计算几何

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1 UVa 11178 Morley's Theorem

#include <iostream>  
#include <cstdio>  
#include <cstring>  
#include <cstdlib>  
#include <algorithm>  
#include <queue>  
#include <vector>  
#include <stack>  
#include <map>  
#include <set>  
#include <cmath>  
#include <cctype>  
#include <ctime>  
#include <cassert>  
  
using namespace std;  
  
#define REP(i, n) for (int i = 0; i < (n); ++i)  
  
struct Point {  
  double x, y;  
  Point(double x = 0.0, double y = 0.0):x(x),y(y) {}  
};  
typedef Point Vector;  
  
const double INF = 1e20;  
const double eps = 1e-10;  
const double PI = acos(-1.0);  
Point A, B, C, D, E, F;  
int N;  
  
Point operator + (const Point& a, const Vector& b) { return Point{a.x + b.x, a.y + b.y}; }  
Vector operator - (const Point& a, const Point& b) { return Vector(a.x - b.x, a.y - b.y); }  
Vector operator * (const Vector& a, double k) { return Vector{a.x * k, a.y * k}; }  
double dot(const Vector& a, const Vector& b) { return a.x * b.x + a.y * b.y; }  
double length(const Vector& a) { return sqrt(dot(a, a)); }  
double angle(const Vector& a, const Vector& b) { return acos(dot(a, b) / length(a) / length(b)); }  
double cross(const Vector& a, const Vector& b) { return a.x * b.y - a.y * b.x; }  
Point read_point() { double x, y; scanf("%lf %lf", &x, &y); return Point{x, y}; }  
Point line_intersection(const Point& p, const Vector& v, const Point& q, const Vector& w) {  
    Vector u = p - q; double t = cross(w, u) / cross(v, w); return p + v * t;  
}  
Vector rotate(const Vector& a, double rad) {  
    return Vector{a.x * cos(rad) - a.y * sin(rad), a.x * sin(rad) + a.y * cos(rad)};  
}  
Point get_D(Point a, Point b, Point c) {  
    Vector v1 = c - b; double a1 = angle(v1, a - b); v1 = rotate(v1, a1 / 3.0);  
    Vector v2 = b - c; double a2 = angle(a - c, v2); v2 = rotate(v2, -a2 / 3.0);  
    return line_intersection(b, v1, c, v2);  
}  
  
int main() {  
#ifdef __AiR_H  
    freopen("in.txt", "r", stdin);  
//    freopen("out.txt", "w", stdout);  
#endif // __AiR_H  
    scanf("%d", &N);  
    while (N--) {  
        A = read_point(); B = read_point(); C = read_point();  
        D = get_D(A, B, C); E = get_D(B, C, A); F = get_D(C, A, B);  
        printf("%.6f %.6f %.6f %.6f %.6f %.6f
", D.x, D.y, E.x, E.y, F.x, F.y);  
    }  
#ifdef __AiR_H  
    printf("Time used = %.2fs
", (double)clock() / CLOCKS_PER_SEC);  
#endif // __AiR_H  
    return 0;  
}  

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