12 2016 档案
摘要：C. New Year and Rating time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output C. New Year and R
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摘要：The Euler function Problem Description The Euler function phi is an important kind of function in number theory, (n) represents the amount of the numb
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摘要：GCD Again Problem Description Do you have spent some time to think and try to solve those unsolved problem after one ACM contest? No? Oh, you must do
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摘要：欧拉函数证明 欧拉函数定义：定义一个数n，φ(n)为不大于n的，与n互质的数的个数。 证明方法用到容斥定理：容斥定理的原理如图： A∪B∪C=A+B+C - A∩B - B∩C - A∩C + A∩B∩C; 欧拉函数证明： 小于等于n的基数有n个，讨论所有n的素因子，只要是素因子的倍数的是都不是n的
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摘要：Assignments Problem Description In a factory, there are N workers to finish two types of tasks (A and B). Each type has N tasks. Each task of type A n
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摘要：Wall Problem Description Once upon a time there was a greedy King who ordered his chief Architect to build a wall around the King's castle. The King w
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摘要：Maple trees Problem Description There are a lot of trees in HDU. Kiki want to surround all the trees with the minimal required length of the rope . As
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摘要：WisKey的眼神 Problem Description WisKey的眼镜有500多度,所以眼神不大好,而且他有个习惯,就是走路喜欢看着地(不是为了拣钱哦^_^),所以大家下次碰见他的时候最好主动打下招呼,呵呵.但是Rabbit总是喜欢扮神秘,一天WisKey去食堂排队等着买饭,突然收到一道短消
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摘要：Surround the Trees Problem Description There are a lot of trees in an area. A peasant wants to buy a rope to surround all these trees. So at first he
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摘要：了解凸包及Graham扫描法 问题描述：二位平面内，给定n个散乱的点，求一个最小凸多边形（凸包），使得n个点都不在凸多边形外。 问题的解决用到Graham算法： 算法步骤： 1.取y坐标最小的一点，作为p0，显然p0一定在凸包上。 2.将p0作为坐标系原点，其他点按极角从小到大排序，从p1开始编号。
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摘要：多边形求重心总结 多边形求重心： 逆时针给出你n边形的n个顶点，求重心利用的原理就是，加权平均，如下图： 将a点作为所有小三角形的公共顶点，那么多边形abcdef的中心=); 三角形的面积：用向量的×乘就可以 s1=向量ac×向量ba；（尽量不要用海伦公式，因为海林公式除法太多，容易卡精度） 三角形
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摘要：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,
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：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
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摘要：Girls and Boys Problem Description the second year of the university somebody started a study on the romantic relations between the students. The rela
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摘要：二分匹配总结 首先讲一下什么是二分图，在一个图中，以边为条件，能将两个端点划分为两个集合的图叫做二分图，如下图： 左图为二分图，右图为简化后的二分图。 接着就是二分图的匹配问题，二分图的匹配就是找一个边的集合，每条边的的顶点的度数为1。 如上图所示，匹配到四条边。 二分图的完美匹配，就是所有的顶点都
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摘要：C. Tram time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output The tram in Berland goes along a
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摘要：Strategic Game Problem Description Bob enjoys playing computer games, especially strategic games, but sometimes he cannot find the solution fast enoug
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摘要：Code Lock Problem Description A lock you use has a code system to be opened instead of a key. The lock contains a sequence of wheels. Each wheel has t
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摘要：Einbahnstrasse Problem Description Einbahnstra e (German for a one-way street) is a street on which vehicles should only move in one direction. One re
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摘要：A Walk Through the Forest Problem Description Jimmy experiences a lot of stress at work these days, especially since his accident made working difficu
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摘要：D. Chloe and pleasant prizes time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output D. Chloe an
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摘要：find the safest road Problem Description XX星球有很多城市，每个城市之间有一条或多条飞行通道，但是并不是所有的路都是很安全的，每一条路有一个安全系数s,s是在 0 和 1 间的实数(包括0，1)，一条从u 到 v 的通道P 的安全度为Safe(P) = s(
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摘要：Here We Go(relians) Again Problem Description The Gorelians are a warlike race that travel the universe conquering new worlds as a form of recreation.
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摘要：In Action Problem Description Since 1945, when the first nuclear bomb was exploded by the Manhattan Project team in the US, the number of nuclear weap
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摘要：/* 数学是硬伤。。。。。。推了半小时推出来一个错误的公式 */ #include #include #include #include #define mod 1000000007 using namespace std; int n,t; /* 推出来的错误公式。。。。。。。 f[n]=f[n-1]+(n-1)*(f[n-1]-1); */ long long a[2000500];...
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摘要：/* 成功水过，哈哈哈，可能数据水吧 */ #include #include #include #include #include #define t_mid (l+r >> 1) #define ls (o= ql && c[ls] <= x) { ans = query(ql,qr,lson,x); if(ans == -1) ...
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摘要：/* 以前做过一个插队的题，这个类似从后往前操作 */ #include #include #include #include #include #define N 600000 using namespace std; struct node { int x,y,z; //每一个操作，z表示这个操作是不是有效的 node(){} node(int a,...
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摘要：HDU Today Problem Description 经过锦囊相助，海东集团终于度过了危机，从此，HDU的发展就一直顺风顺水，到了2050年，集团已经相当规模了，据说进入了钱江肉丝经济开发区500强。这时候，XHD夫妇也退居了二线，并在风景秀美的诸暨市浬浦镇陶姚村买了个房子，开始安度晚年了。这
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摘要：最短路 Problem Description 在每年的校赛里，所有进入决赛的同学都会获得一件很漂亮的t-shirt。但是每当我们的工作人员把上百件的衣服从商店运回到赛场的时候，却是非常累的！所以现在他们想要寻找最短的从商店到赛场的路线，你可以帮助他们吗？ Input 输入包括多组数据。每组数据第一
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摘要：Pseudoforest Problem Description In graph theory, a pseudoforest is an undirected graph in which every connected component has at most one cycle. The
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摘要：Connect the Cities Problem Description In 2100, since the sea level rise, most of the cities disappear. Though some survived cities are still connecte
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摘要：Jungle Roads Problem Description The Head Elder of the tropical island of Lagrishan has a problem. A burst of foreign aid money was spent on extra roa
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摘要：继续畅通工程 Problem Description 省政府“畅通工程”的目标是使全省任何两个村庄间都可以实现公路交通（但不一定有直接的公路相连，只要能间接通过公路可达即可）。现得到城镇道路统计表，表中列出了任意两城镇间修建道路的费用，以及该道路是否已经修通的状态。现请你编写程序，计算出全省畅通需要
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摘要：还是畅通工程 Problem Description 某省调查乡村交通状况，得到的统计表中列出了任意两村庄间的距离。省政府“畅通工程”的目标是使全省任何两个村庄间都可以实现公路交通（但不一定有直接的公路相连，只要能间接通过公路可达即可），并要求铺设的公路总长度为最小。请计算最小的公路总长度。 Inp
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摘要：畅通工程 Problem Description 某省调查城镇交通状况，得到现有城镇道路统计表，表中列出了每条道路直接连通的城镇。省政府“畅通工程”的目标是使全省任何两个城镇间都可以实现交通（但不一定有直接的道路相连，只要互相间接通过道路可达即可）。问最少还需要建设多少条道路？ Input 测试输入
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摘要：Eddy's picture Problem Description Eddy begins to like painting pictures recently ,he is sure of himself to become a painter.Every day Eddy draws pict
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摘要：Constructing Roads Problem Description There are N villages, which are numbered from 1 to N, and you should build some roads such that every two villa
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摘要：Buy the Ticket Problem Description The \\\\\\\"Harry Potter and the Goblet of Fire\\\\\\\" will be on show in the next few days. As a crazy fan of Har
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摘要：C. Arpa's loud Owf and Mehrdad's evil plan time limit per test 1 second memory limit per test 256 megabytes input standard input output standard outpu
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摘要：B. Arpa’s obvious problem and Mehrdad’s terrible solution time limit per test 1 second memory limit per test 256 megabytes input standard input output
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摘要：Last non-zero Digit in N! Problem Description The expression N!, read as "N factorial," denotes the product of the first N positive integers, where N
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摘要：Disharmony Trees Problem Description One day Sophia finds a very big square. There are n trees in the square. They are all so tall. Sophia is very int
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