http://www.lightoj.com/volume_showproblem.php?problem=1058 题意:给你顶点,问能够成多少个平行四边形. 思路:开始想使用长度来扫描有多少根,但是好像坐标太大似乎不可行.其实我们可以通过找所有线段的中点的重合个数来计算有几个平行四边形,这种通过别的性质来判断几何关系的思维是解几何题的基础,当作入门? /** @Date : 2016-12-02-21.49 * @Author : Lweleth (SoungEarlf@gmail.com)…

链接: https://vjudge.net/problem/LightOJ-1058 题意: There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie on these points. In other words, find the number of 4-element subsets o…

1058 - Parallelogram Counting There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie on these points. In other words, find the number of 4-element subsets of these points tha…

Description There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie on these points. In other words, find the number of 4-element subsets of these points that can be written a…

1058 - Parallelogram Counting    PDF (English) Statistics Forum Time Limit: 2 second(s) Memory Limit: 32 MB There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie on these po…

      Parallelogram Counting Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 6895   Accepted: 2423 Description There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices…

lightoj 1148 Mad Counting 链接:http://lightoj.com/volume_showproblem.php?problem=1148 题意:民意调查,每一名公民都有盟友,问最少人数. 思路:考察的知识点有两个:第一是整数相乘取上整:第二是容器大小(ps:不能算一个知识点,只能算一个坑点). 做题思路:排序,如果被调查的人有相同盟友人数(n)的个数(cnt)大于这个数+1,即:(cnt > n+1), 容器已满,只能新开辟一个容器来装盟友. 代码: #includ…

Parallelogram Counting Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 5749   Accepted: 1934 Description There are n distinct points in the plane, given by their integer coordinates. Find the number of parallelograms whose vertices lie o…

题目链接:http://codeforces.com/gym/101149/problem/K 题目大意: 给你两个点a,b.一个人在a点,一个人在b点,b点的人要追杀a的点,他的跑步速度是a的两倍.如果a点的人能在b点追击到之前回到a点这个位置,那么这个人就是安全的(b点的人追击a点的人的追击方案是:一直朝着a点的人所在的位置奔跑过去).问,这个人的安全区域是多少? 思路:几何果然不会= =,连sb题都没想到 因为是面积,所以说两点之间的距离就决定了最后的结果.因为题目给出的是单位面积.所以对…

先上题目: 1148 - Mad Counting   PDF (English) Statistics Forum Time Limit: 0.5 second(s) Memory Limit: 32 MB Mob was hijacked by the mayor of the Town "TruthTown". Mayor wants Mob to count the total population of the town. Now the naive approach to…