题目大意: 给定n条线段 接下来n行是端点信息 接下来询问 a b 是否相交 若a与c相交 b与c相交 ,那么a与b就是相交的 先判断任两条线段是否相交 再用folyd #include <cstdio> #include <cmath> #include <algorithm> #include <stdio.h> #include <string.h> using namespace std; ; double add(double a,do…

题目大意:给出一些线段,然后判断这些线段的投影是否有可能存在一个公共点.   分析:如果这些线段的投影存在一个公共点,那么过这个公共点作垂线一定与所有的直线都想交,于是题目转化成是否存在一个直线可以经过所有的线段,考虑线段并不多,所以可以枚举任意两点当作直线......   代码如下: ==========================================================================================================…

题目大意: 将所有物体抽象成一段横向的线段 给定房子的位置和人行道的位置 接下来给定n个障碍物的位置 位置信息为(x1,x2,y) 即x1-x2的线段 y相同因为是横向的 求最长的能看到整个房子的一段人行道的长度 若不在 y(房子)和y(人行道)之间的 不会有视野的阻碍 注意边界处理 因为盲区可能包含在人行道内 也可能超出 #include <cstdio> #include <algorithm> #include <cmath> using namespace st…

Jack Straws In the game of Jack Straws, a number of plastic or wooden "straws" are dumped on the table and players try to remove them one-by-one without disturbing the other straws. Here, we are only concerned with if various pairs of straws are…

题目链接:POJ 3304 Problem Description Given n segments in the two dimensional space, write a program, which determines if there exists a line such that after projecting these segments on it, all projected segments have at least one point in common. Input…

题目传送门:POJ 3304 Segments Description Given n segments in the two dimensional space, write a program, which determines if there exists a line such that after projecting these segments on it, all projected segments have at least one point in common. Inp…

题意:在二维平面中,给定一些线段,然后判断在某直线上的投影是否有公共点. 转化,既然是投影,那么就是求是否存在一条直线L和所有的线段都相交. 证明: 下面给出具体的分析:先考虑一个特殊的情况,即n=1的时候,如下图,线段AB在直线L上的投影为线段A'B',则过任意介于A'B'之间的点C'做直线L的垂线必交线段AB与一点C:反之,过线段AB之间任意一点C做直线L的垂线,垂足必定落在A'B'之间. 不难将此结论推广到n条线段的情况,假设存在一满足题意的直线L,则设点A为各个线段在L上投影的公共点,那…

Pick-up sticks Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 11884   Accepted: 4499 Description Stan has n sticks of various length. He throws them one at a time on the floor in a random way. After finishing throwing, Stan tries to fin…

Intersecting Lines Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 13605   Accepted: 6049 Description We all know that a pair of distinct points on a plane defines a line and that a pair of lines on a plane will intersect in one of three…

链接: http://poj.org/problem?id=1039 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=22013#problem/B Pipe Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 8350   Accepted: 2501 Description The GX Light Pipeline Company started to prep…