岁月流风、、

Description Many geometry（几何）problems were designed in the ACM/ICPC. Andnow, I also prepare a geometry problem for this final exam. According to theexperience of many ACMers, geometry problems are al

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1756         判断点是否在多边形内部        从点p做一条射线，看射线和多边形的交点有几个,奇数个为相交，偶数个不相交。。。        具体做法如下:             以点P为端点，向左方作射线L，由于多边形是有界的，所以射线L的左端一定在多边形外，考