昨天吉老师讲了皮克定理 皮克定理用于计算点阵中顶点在格点上的多边形面积.对于一个顶点全部在格点上的多边形来说,它的面积计算有如下特点: 如果用a表示位于多边形内部的格点数,b表示位于多边形边界上的格点数,则多边形面积可表示为S = a + b/2 – 1 . 皮克定理用于计算点阵中顶点在格点上的多边形面积.对于一个顶点全部在格点上的多边形来说,它的面积计算有如下特点: 如果用a表示位于多边形内部的格点数,b表示位于多边形边界上的格点数,则多边形面积可表示为S = a + b/2 – 1 . A…

Count the string Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 8845    Accepted Submission(s): 4104 Problem Description It is well known that AekdyCoin is good at string problems as well as n…

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=4255 A Famous Grid Description Mr. B has recently discovered the grid named "spiral grid".Construct the grid like the following figure. (The grid is actually infinite. The figure is only a small par…

Count primes 题目连接: http://acm.split.hdu.edu.cn/showproblem.php?pid=5901 Description Easy question! Calculate how many primes between [1...n]! Input Each line contain one integer n(1 <= n <= 1e11).Process to end of file. Output For each case, output…

It is well known that AekdyCoin is good at string problems as well as number theory problems. When given a string s, we can write down all the non-empty prefixes of this string. For example:  s: "abab"  The prefixes are: "a", "ab&…

题目传送门:http://acm.hdu.edu.cn/showproblem.php?pid=6470 Count Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 301    Accepted Submission(s): 127 Problem Description Farmer John有n头奶牛.某天奶牛想要数一数有多少头奶牛…

链接:http://acm.hdu.edu.cn/showproblem.php?pid=1705 [题意] 给出平面上三个点坐标,求围成的三角形内部的点数 做这道题需要先了解下皮克定理. 百度百科:皮克定理是指一个计算点阵中顶点在格点上的多边形面积公式,该公式可以表示为2S=2a+b-2,其中a表示多边形内部的点数,b表示多边形边界上的点数,s表示多边形的面积. 多边形边界上的整数点怎么求呢? 当然是gcd啦~~  gcd(x1-x2, y1-y2)就是这条边上整数点的个数.但是仅仅一条边是不…

Count the Buildings Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 2521    Accepted Submission(s): 817 Problem Description There are N buildings standing in a straight line in the City, numbere…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=6016 题意:给定男羊和女羊的朋友关系,即给定一个图,问从任意一只羊开始连续数四只不相同的羊的方法数. 这题挺简单的就是需要动一下脑子,我们只要找到关系A-B-C-D即可,且关系址建立在男女羊之间. 就是说我们只要找到 男羊-女羊-男羊-女羊,或者 女羊-男羊-女羊-男羊 即可. 于是那只要找到任意一种方式的总数然后乘2即可. 拿后一种关系为例. ans[i]表示i号女羊有几个男羊朋友vc[i]存储与…

hdu5901题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5901 code vs 3223题目链接:http://codevs.cn/problem/3223/ 思路:主要是用了一个Meisell-Lehmer算法模板,复杂度O(n^(2/3)).讲道理,我不是很懂(瞎说什么大实话....),下面输出请自己改 #include<bits/stdc++.h> using namespace std; typedef long long LL;…