hqd_acm的专栏

概念凸包(Convex Hull)是一个计算几何（图形学）中的概念。用不严谨的话来讲，给定二维平面上的点集，凸包就是将最外层的点连接起来构成的凸多边型，它能包含点集中所有点的。严谨的定义和相关概念参见维基百科：凸包。这个算法是由数学大师葛立恒(Graham)发明的，他曾经是美国数学学会(AMS)主席、AT&T首席科学家以及国际杂技师协会(IJA)主席。（太汗了，这位大牛还会玩杂技~） 问题给定平面上的二维点集，求解其凸包。 过程1. 在所有点中选取y坐标最小的一点H，当作基点。如果存在多个点的y坐标

<br />1173: Circle More AlikeResultTIME LimitMEMORY LimitRun TimesAC TimesJUDGE3s8192K661258Standard<br />1st Jilin University ACM International Collegiate Programming Contest<br />In this problem, you are to write a program to calculate the roundness of

The Circumference of the CircleTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 4952 Accepted: 3269<br />DescriptionTo calculate the circumference of a circle seems to be an easy task - provided you know its diameter. But what if you don't? <br />

<br /> <br /> TriangleTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 2866 Accepted: 1218<br />Description<br />A lattice point is an ordered pair (x, y) where x and y are both integers. Given the coordinates of the vertices of a triangle (which

<br />IntersectionTime Limit: 1000MS Memory Limit: 10000KTotal Submissions: 5892 Accepted: 1484<br />DescriptionYou are to write a program that has to decide whether a given line segment intersects a given rectangle. <br /><br />An example: <br />line:

最小圆覆盖比赛的过程太搞了，丢不起这人。