提示: 欢迎访问OurACM平台。
Problem 1611 Hero's circle

Accept: 81    Submit: 300
Time Limit: 1000 mSec    Memory Limit : 32768 KB

Problem Description

The hero and oaiei is playing a game now. The hero draws arbitrary quadrilateral in a plane, the four vertices of the quadrilateral are A, B, C, D respectively, and oaiei must draw a circle on the plane, the circle must go through the quadrilateral' four vertices . Can you help oaiei determine whether he can draw a circle through the four points?

Input

There are multiple tests. For each test, threre contains four lines.

The first line contains two floating-point number Ax Ay, denoting that the coordinate of point A is (Ax, Ay).

The second line contains two floating-point number Bx By, denoting that the coordinate of point B is (Bx, By).

The third line contains two floating-point number Cx Cy, denoting that the coordinate of point C is (Cx, Cy).

The fourth line contains two floating-point number Dx Dy, denoting that the coordinate of point D is (Dx, Dy).

We guarantee that the four points are different and the order are given arbitrarily.

Output

For each test, if oaiei can draw a circle, then you should output “Yes”, otherwise you should output “No” on a single line(quotes for clarity only).

Sample Input

0.000 0.000 1.000 0.000 1.000 1.000 0.000 1.000 0.000 0.000 1.000 0.000 1.000 1.000 2.000 1.000

Sample Output

Yes No

Source

FOJ月赛-2008年6月 -- Heroes Happen Here

Submit  Back  Status  Discuss