如何将无序的多边形顶点集合，排序成逆时针顺序!这个正是凸包算法前面的一些准备工作!-how to disorderly polygon vertex assembly, sequencing into a counter-clockwise order! This is why the convex hull algorithm front of some preparation work!

实现点集凸包的算法，把众多随机分布的点用一条折线以最小的长度使其全部包括其中-Achieve point set convex hull algorithms, the number of random distribution of points with a polyline with a minimum length of it all including the

算法课程中一个给出N个点和坐标，求取一个凸包的程序-Algorithm for a course coordinates are given N points and strike a convex program