题解： Intersecting Lines（判断两直线关系，求交点）

最新推荐文章于 2025-05-27 11:01:44 发布

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最新推荐文章于 2025-05-27 11:01:44 发布 · 523 阅读

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该博客讨论如何根据平面上的四个点判断两条直线的交点情况，包括平行、重合和相交，并指出程序设计中可能遇到的问题及其解决策略。

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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 (i.e. they are the same line), 3) intersect in a point. In this problem you will use your algebraic knowledge to create a program that determines how and where two lines intersect.

Your program will repeatedly read in four points that define two lines in the x-y plane and determine how and where the lines intersect. All numbers required by this problem will be reasonable, say between -1000 and 1000.

    Input
    
  
   The first line contains an integer N between 1 and 10 describing how many pairs of lines are represented. The next N lines will each contain eight integers. These integers represent the coordinates of four points on the plane in the order x1y1x2y2x3y3x4y4. Thus each of these input lines represents