题目链接:https://vjudge.net/contest/276358#problem/C 题目大意:给你n条线段,问你是否存在一条线段使得所有的线段在这条直线的投影至少具有一个交点? 具体思路:这个题转换一下思路,假设存在一条直线与所有的线段都相交,那么这条直线的垂线就是题目中所求的直线,我们可以把所有的端点都遍历一遍,询问一下看有没有符合条件的直线就可以了. AC代码: /*********************************************************

Pick-up sticks Time Limit: 4000/2000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 1872    Accepted Submission(s): 706 Problem Description Stan has n sticks of various length. He throws them one at a time on the fl

Jack Straws Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 2911   Accepted: 1322 Description 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 witho

You can Solve a Geometry Problem too Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 6837 Accepted Submission(s): 3303 Problem Description Many geometry(几何)problems were designed in the ACM/ICPC. A

You can Solve a Geometry Problem too Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 6425    Accepted Submission(s): 3099 Problem Description Many geometry(几何)problems were designed in the ACM/I

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

题目大意: 给定n条线段的端点 依次放上n条线段 判断最后在最上面(不被覆盖)的线段有哪些 到当前线段后 直接与之前保存的未被覆盖的线段判断是否相交就可以了 #include <cstdio> #include <algorithm> #include <string.h> #include <set> #include <cmath> #define INF 0x3f3f3f3f using namespace std; ; double ad

1840: Jack Straws  Time Limit(Common/Java):1000MS/10000MS     Memory Limit:65536KByteTotal Submit: 154            Accepted:119 Description In the game of Jack Straws, a number of plastic or wooden "straws" are dumped on the table and players try

一 题面 POJ1127 二 分析 在平面几何中,判断两线段相交的方法一般是使用跨立实验.但是这题考虑了非严格相交,即如何两个线段刚好端点相交则也是相交的,所以还需要使用快速排斥实验. 这里参考并引用了TangMoon 博客. 1.快速排斥实验 由于两个点作为矩形的两个斜对角线端点可以确定一个矩形,则根据两个点确定一个向量,两个向量显然可以确定两个矩形. 对于快速排斥实验,也可尝试逆向思维,如果判断让两个向量确定的两个矩形是否相交部分,相当于判断两个矩形没有相交部分的反. 具体条件就是a.其中一

Segment set Problem Description A segment and all segments which are connected with it compose a segment set. The size of a segment set is the number of segments in it. The problem is to find the size of some segment set.   Input In the first line th

最近需要用到矩形相交算法的简单应用,所以特地拿一个很简单的算法出来供新手参考,为什么说是给新手的参考呢因为这个算法效率并不是很高,但是这个算法只有简简单单的三行.程序使用了两种方法来判断是否重叠/相交,如果有兴趣可以看一下,如果觉得有bug可以留言.代码仅供参考. C#中矩形的方法为Rectangl(起始点坐标, 矩形的大小)或Rectangl(起始点x坐标, 起始点y坐标, 矩形宽, 矩形高),起始点为矩形区域的左上角. 方法一 姑且叫做“井字法”吧,延长其中一个矩形的四边使其形成一“井”字(

You can Solve a Geometry Problem too Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 199    Accepted Submission(s): 132   Problem Description Many geometry(几何)problems were designed in the ACM/

http://poj.org/problem?id=2653 题目大意:有n根各种长度的棍   一同洒在地上 求在最上面的棍子有那几个 分析:  我刚开始想倒着遍历  因为n是100000   想着会超时吧  后来一看说  在上面的不会超过1000个 这就放心了 简单优化一下就过了 最后一个肯定是在最上面的 让后从他的下一个开始  每一个跟他相交的都是在他下面的  下一次就直接不循环他了 但是一直wa   彻底懵逼了 后来看了学长博客  他是正这循环  只要有跟他相交的就跳出  然后我就正这便利

#include<cstdio> #include<cmath> #include<iostream> #include<algorithm> #include<vector> #include<stack> #include<cstring> #include<queue> #include<set> #include<string> #include<map> #incl

Pick-up sticks Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 11335   Accepted: 4250 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

题 利用叉积解方程 #include <cstdio> #define MAX 1<<31 #define dd double int xmult(dd x1,dd y1,dd x2,dd y2,dd x,dd y){ return (x1-x)*(y2-y)-(x2-x)*(y1-y); } int main(){ int n; dd x1,y1,x2,y2,x3,y3,x4,y4; scanf("%d",&n); puts("INTERSE

传统解法 题目来自 leetcode 335. Self Crossing. 题意非常简单,有一个点,一开始位于 (0, 0) 位置,然后有规律地往上,左,下,右方向移动一定的距离,判断是否会相交(self crossing). 一个很容易想到的方案就是求出所有线段,然后用 O(n^2) 的时间复杂度两两判断线段是否相交,而线段相交的判断,可以列个二元一次方程求解(交点).这个解法非常容易想到,但是实际操作起来比较复杂,接下去介绍利用向量的解法. 向量解法 简单回顾下向量,具体的自行谷歌.向量就

http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1264 三角形的有向面积:a.x*b.y+b.x*c.y+c.x*a.y - a.x*c.y - c.x*b.y - b.x*a.y; 上面得到的即是以点A,B,C三点组成的三角形面积的两倍. 如果area >0 则点A,B,C呈逆时针排列. 如果area<0  则点A,B,C呈顺时针排列. 如果area=0  则点A,B,C三点共线. 那么判断线段1(两个端点poin

转载自 http://blog.csdn.net/william001zs/article/details/6213485 矢量 如果一条线段的端点是有次序之分的话,那么这种线段就称为 有向线段,如果有向线段p1p2的起点p1在坐标的原点,则可以把它称为矢量 p2 矢量的加减 设二维矢量 P = (x1, y1), Q = (x2, y2),则 P + Q = (x1 + x2, y1 + y2), P - Q = (x1 - x2, y1 - y2),且有 P + Q = Q + P, P -

简单的计算几何题,判断两线段是否相交.将相交的两线段使用并查集归到一类中.查询时输出线段对应集合中元素的个数. #include<stdio.h> struct Point{ double x,y; }; struct Segment{ Point s,e; }node[1010]; int n,parent[1010]; int getAbs(int value) { if(value>=0)return value; return -value; } int getParent(in

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 find the top sticks, that is these sticks such that there is no stick on top of them. Stan has noticed that the la