Problem Intersecting Lines (POJ 1269) 题目大意 给定两条直线,问两条直线是否重合,是否平行,或求出交点. 解题分析 主要用叉积做,可以避免斜率被0除的情况. 求交点P0: 已知P1 P2 P3 P4 运用 P0P1 X P0P2 = 0 和 P0P3 X P0P4 = 0 C++ 用%.2lf g++ 用 %.2f!!! C++ 用%.2lf g++ 用 %.2f!!! C++ 用%.2lf g++ 用 %.2f!!! 参考程序 #include <cstd…

// 直线相交 POJ 1269 // #include <bits/stdc++.h> #include <iostream> #include <cstdio> #include <cstdlib> #include <algorithm> #include <math.h> using namespace std; #define LL long long typedef pair<int,int> pii; con…

两条直线可能有三种关系:1.共线     2.平行(不包括共线)    3.相交. 那给定两条直线怎么判断他们的位置关系呢.还是用到向量的叉积 例题:POJ 1269 题意:这道题是给定四个点p1, p2, p3, p4,直线L1,L2分别穿过前两个和后两个点.来判断直线L1和L2的关系 这三种关系一个一个来看: 1. 共线. 如果两条直线共线的话,那么另外一条直线上的点一定在这一条直线上.所以p3在p1p2上,所以用get_direction(p1, p2, p3)来判断p3相对于p1p2的关…

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…

题目链接:POJ 1269 Problem 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 ways: 1) no intersection because they are parallel, 2) intersect in a line becau…

题目传送门:POJ 1269 Intersecting Lines 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 ways: 1) no intersection because they are parallel, 2) intersect in…

题目链接:http://poj.org/problem?id=1269 题目大意:给出四个点的坐标x1,y1,x2,y2,x3,y3,x4,y4,前两个形成一条直线,后两个坐标形成一条直线.然后问你是否平行,重叠或者相交,如果相交,求出交点坐标. 算法:二维几何直线相交+叉积 解法:先用叉积判断是否相交,如果相交的话,设交点坐标为p0(x0,y0).向量(p0p1)和(p0p2)的叉积为0,有(x1-x0)*(y2-y0)-(y1-y0)*(x2-x0)=0;同理,求出p0和p3p4直线的式子.…

题目链接:http://poj.org/problem?id=1269 #include<cstdio> #include<cstring> #include<cmath> #include<iostream> #include<algorithm> #include<queue> using namespace std; ; ; const int INF = 0x3f3f3f; ; const double PI = acos(-…

题链: http://poj.org/problem?id=1269 题解: 计算几何,直线交点 模板题,试了一下直线的向量参数方程求交点的方法. (方法详见<算法竞赛入门经典——训练指南>P257) 代码: #include<cstdio> #include<cstring> #include<iostream> using namespace std; struct Point{ double x,y; Point(double _x=0,double…

题目链接:http://poj.org/problem?id=1269 Time Limit: 1000MS Memory Limit: 10000K 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 ways: 1) no intersection b…