hdu-5738 Eureka(组合计数+极角排序)

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hdu-5738 Eureka(组合计数+极角排序)

题目链接: Eureka Time Limit: 8000/4000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others) Problem Description Professor Zhang draws n points on the plane, which are conveniently labeled by 1,2,...,n. The i-th point is at (xi,yi). Professor…

HDU 5738 Eureka（极角排序）

[题目链接] http://acm.hdu.edu.cn/showproblem.php?pid=5738 [题目大意] 给出平面中一些点,在同一直线的点可以划分为一个集合,问可以组成多少包含元素不少于2的集合. [题解] 最重要的还是处理点重合,和线重复计算的问题,对于每个点,进行极角排序,作为端点,然后统计包含它的每个集合即可.思路非常简单,然而比赛的时候……一脸懵逼地用map,pair,然后转战hash.看起来对于计算几何的敏感度还有待加强. [代码] #include <cstdio>…

hdu 5738 Eureka 极角排序+组合数学

Eureka Time Limit: 8000/4000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 2317 Accepted Submission(s): 678 Problem Description Professor Zhang draws n points on the plane, which are conveniently labeled by 1,2,…

HDU 5738 Eureka 统计共线的子集个数

Eureka 题目连接: http://acm.hdu.edu.cn/showproblem.php?pid=5738 Description Professor Zhang draws n points on the plane, which are conveniently labeled by 1,2,...,n. The i-th point is at (xi,yi). Professor Zhang wants to know the number of best sets. As…

HDU 5738 Eureka

传送门题目大意: 给出平面上的$n$个点,每个点有唯一的标号($\text{label}$),这$n$个标号的集合记作$S$,点可能重合.求满足下列条件的$S$的子集$T$的数目: 1. $|T|\ge 2$ 2.$T$中的点共线 Solution: 只包含一个点的符合条件的子集$T$的数目很容易计算,以下我们只考虑其中至少有两个不同(指坐标不同,下同)点的符合条件的子集$T$(以下简称子集)的数目. 考虑两不同点$u, v$所决定的直线上的点,将这些点的集合记作$P_{uv}$,考虑$P_{…

2017ACM暑期多校联合训练 - Team 7 1008 HDU 6127 Hard challenge （极角排序）

题目链接 Problem Description There are n points on the plane, and the ith points has a value vali, and its coordinate is (xi,yi). It is guaranteed that no two points have the same coordinate, and no two points makes the line which passes them also passes…