计算几何: 最基本的计算几何,差积 旋转
Morley's Theorem
| Time Limit: 3000MS | Memory Limit: Unknown | 64bit IO Format: %lld & %llu |
Submit Status
Description
Problem D
Morley’s Theorem
Input: Standard Input
Output: Standard Output
Morley’s theorem states that that the lines trisecting the angles of an arbitrary plane triangle meet at the vertices of an equilateral triangle. For example in the figure below the tri-sectors of angles A, B and C has intersected and created an equilateral triangle DEF.

Of course the theorem has various generalizations, in particular if all of the tri-sectZ??http://www.2cto.com/kf/ware/vc/" target="_blank" class="keylink">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"131" height="24" src="https://www.cppentry.com/upload_files/article/49/1_jpwbg__.gif" alt="\">. This six integers actually indicates that the Cartesian coordinates of point A, B and C are
respectively. You can assume that the area of triangle ABC is not equal to zero,
and the points A, B and C are in counter clockwise order.
Output
For each line of input you should produce one line of output. This line contains six floating point numbers
separated by a single space. These six floating-point actually means that the Cartesian coordinates of D, E and F are
respectively. Errors less than
will be accepted.
Sample Input Output for Sample Input
2 1 1 2 2 1 2 0 0 100 0 50 50 |
1.316987 1.816987 1.183013 1.683013 1.366025 1.633975 56.698730 25.000000 43.301270 25.000000 50.000000 13.397460 |
Problemsetters: Shahriar Manzoor
Special Thanks: Joachim Wulff
Source
Root :: Prominent Problemsetters :: Shahriar ManzoorRoot :: AOAPC I: Beginning Algorithm Contests -- Training Guide (Rujia Liu) :: Chapter 4. Geometry :: Geometric Computations in 2D :: Examples
#include#include #include #include #include using namespace std; const double eps=1e-8; int dcmp(double x) { if(fabs(x)