题目:POJ1269 题意:给你两条直线的坐标,判断两条直线是否共线.平行.相交,若相交,求出交点. 思路:直线相交判断.如果相交求交点. 首先先判断是否共线,之后判断是否平行,如果都不是就直接求交点了. #include <iostream> #include <string.h> #include <stdio.h> #include <algorithm> #include <math.h> #include <queue> #…

Intersecting Lines Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 15145   Accepted: 6640 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…

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 because they are on top of one another…

题目大意:求两条直线的交点坐标. 解题关键:叉积的运用. 证明: 直线的一般方程为$F(x) = ax + by + c = 0$.既然我们已经知道直线的两个点,假设为$(x_0,y_0), (x_1, y_1)$,那么可以得到$a = {y_0} - {y_1}$,$b = x_1 – x_0$,$c = x_0y_1 – x_1y_0$. 因此我们可以将两条直线分别表示为 ${F_0}(x) = {\rm{ }}{a_0}x{\rm{ }} + {\rm{ }}{b_0}y{\rm{ }}…

Intersecting Lines Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 15478   Accepted: 6751 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…

http://poj.org/problem?id=1269 题目大意:给四个点,求前两个点所构成的直线和后两个点所构成的直线的位置关系(平行,重合,相交),如果是相交,输出交点坐标. —————————————————————— http://blog.csdn.net/zxy_snow/article/details/6341282 这个人的博客有详细的证明过程,这里直接拿来用即可. 应当优先判断向量平行,这样再判断是否重合能更方便些. #include<cstdio> #include&…

题目:http://poj.org/problem?id=1269 相关知识: 叉积求面积:https://www.cnblogs.com/xiexinxinlove/p/3708147.html什么是叉积:https://blog.csdn.net/sunbobosun56801/article/details/78980467        其二维:https://blog.csdn.net/qq_38182397/article/details/80508303计算交点:    方法1:面…

题意: 二维平面,给两条线段,判断形成的直线是否重合,或是相交于一点,或是不相交. 解法: 简单几何. 重合: 叉积为0,且一条线段的一个端点到另一条直线的距离为0 不相交: 不满足重合的情况下叉积为0 相交于一点: 直线相交的模板 代码: #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath> #include &l…

题意:给两条直线,判断相交,重合或者平行 思路:判断重合可以用叉积,平行用斜率,其他情况即为相交. 求交点: 这里也用到叉积的原理.假设交点为p0(x0,y0).则有: (p1-p0)X(p2-p0)=0 (p3-p0)X(p2-p0)=0 展开后即是 (y1-y2)x0+(x2-x1)y0+x1y2-x2y1=0 (y3-y4)x0+(x4-x3)y0+x3y4-x4y3=0 将x0,y0作为变量求解二元一次方程组. 假设有二元一次方程组 a1x+b1y+c1=0; a2x+b2y+c2=0…

题目传送门 题意:判断两条直线的位置关系,共线或平行或相交 分析:先判断平行还是共线,最后就是相交.平行用叉积判断向量,共线的话也用叉积判断点,相交求交点 /************************************************ * Author :Running_Time * Created Time :2015/10/24 星期六 09:08:55 * File Name :POJ_1269.cpp *********************************…