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Lifting the Stone Problem Description There are many secret openings in the floor which are covered by a big heavy stone. When the stone is lifted up, 阅读全文
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You can Solve a Geometry Problem too Problem Description Many geometry（几何）problems were designed in the ACM/ICPC. And now, I also prepare a geometry p 阅读全文
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计算几何-判断线段相交 判断两线段是否相交： 快速排斥 跨立实验（这两个词也是我看博客的时候看到的，觉得挺高大上的就拿过来用了，哈哈哈） 1. 快速排斥：就是初步的判断一下，两条线段是不是相交，以两条线段为对角线的矩形，如果不重合的话，那么两条线段一定不可能相交。看下图： 1.线段ab的低点低于cd 阅读全文
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Shape of HDU Problem Description 话说上回讲到海东集团推选老总的事情，最终的结果是XHD以微弱优势当选，从此以后，“徐队”的称呼逐渐被“徐总”所取代，海东集团（HDU）也算是名副其实了。创业是需要地盘的，HDU向钱江肉丝高新技术开发区申请一块用地，很快得到了批复，据说 阅读全文
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凸多边形 凸多边形的判断方法： 1）角度法： 判断每个顶点所对应的内角是否小于180度，如果小于180度，则是凸的，如果大于180度，则是凹多边形。 2）凸包法： 这种方法首先计算这个多边形的凸包，关于凸包的定义在此不再赘述，首先可以肯定的是凸包肯定是一个凸多边形。如果计算出来的凸多边形和原始多边形 阅读全文
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Cat vs. Dog Problem Description The latest reality show has hit the TV: ``Cat vs. Dog''. In this show, a bunch of cats and dogs compete for the very p 阅读全文
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Uncle Tom's Inherited Land* Problem Description Your old uncle Tom inherited a piece of land from his great-great-uncle. Originally, the property had 阅读全文
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50 years, 50 colors Problem Description On Octorber 21st, HDU 50-year-celebration, 50-color balloons floating around the campus, it's so nice, isn't i 阅读全文
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Air Raid Problem Description Consider a town where all the streets are one-way and each street leads from one intersection to another. It is also know 阅读全文
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Machine Schedule Problem Description As we all know, machine scheduling is a very classical problem in computer science and has been studied for a ver 阅读全文