UVA11178 Morley's Theorem(基础模板)

题目链接

题意：给出A，B, C点坐标求D,E,F坐标，其中每个角都被均等分成三份  

求出 ABC的角a, 由 BC 逆时针旋转 a/3 得到BD,然后 求出 ACB 的角a2, 然后 由 BC顺时针 旋转 a2 / 3得到 DC,然后就交点

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 #include <cstring>
 5 #include <cmath>
 6 using namespace std;
 7 struct Point
 8 {
 9     double x, y;
10 };
11 typedef Point Vector;
12 Vector operator + (Vector A, Vector B)
13 {
14     Vector C;
15     C.x = A.x + B.x;
16     C.y = A.y + B.y;
17     return C;
18 }
19 Vector operator - (Vector A, Vector B)
20 {
21     Vector C;
22     C.x = A.x - B.x;
23     C.y = A.y - B.y;
24     return C;
25 }
26 Vector operator *(Vector A, double b)
27 {
28     Vector C;
29     C.x = A.x * b;
30     C.y = A.y * b;
31     return C;
32 }
33 Point read_point()
34 {
35     Point temp;
36     scanf("%lf%lf", &temp.x, &temp.y);
37     return temp;
38 }
39 double Dot(Vector A, Vector B)
40 {
41     return A.x * B.x + A.y * B.y;
42 }
43 double Length(Vector A)
44 {
45     return sqrt(Dot(A, A));
46 }
47 double Angle(Vector A, Vector B)
48 {
49     return acos(Dot(A, B) / Length(A) / Length(B));
50 }
51 Vector Rotate(Vector A, double rad)
52 {
53     Vector C;
54     C.x = A.x * cos(rad) - A.y * sin(rad);
55     C.y = A.x * sin(rad) + A.y * cos(rad);
56     return C;
57 }
58 double Cross(Vector A, Vector B)
59 {
60     return A.x * B.y - A.y * B.x;
61 }
62 Point GetLineIntersection(Point P, Vector v, Point Q, Vector w)
63 {
64     Vector u = P - Q;
65     double t = Cross(w, u) / Cross(v, w);
66     return P + v * t;
67 }
68 Point getD(Point A, Point B, Point C)
69 {
70     Vector v1 = C - B;
71     double a1 = Angle(A - B, v1);
72     v1 = Rotate(v1, a1 / 3);
73
74     Vector v2 = B - C;
75     double a2 = Angle(A - C, v2);
76     v2 = Rotate(v2, -a2 / 3);
77
78     return GetLineIntersection(B, v1, C, v2);
79
80 }
81 int main()
82 {
83     int T;
84     Point A, B, C, D, E, F;
85     scanf("%d", &T);
86     while (T--)
87     {
88         A = read_point();
89         B = read_point();
90         C = read_point();
91         D = getD(A, B, C);
92         E = getD(B, C, A);
93         F = getD(C, A, B);
94
95         printf("%.6lf %.6lf %.6lf %.6lf %.6lf %.6lf\n", D.x, D.y, E.x, E.y, F.x, F.y);
96
97     }
98     return 0;
99 }

UVA11178 Morley's Theorem(基础模板)