UVA_378_Intersecting Lines

<pre name="code" class="cpp">#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#include<numeric>
#pragma warning(disable:4996)
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
using std::priority_queue;
class Point
{
public:
double x, y;
Point() {}
Point(const double &X,const double &Y)
{
x = X;
y = Y;
}
};
class Line
{
public:
double a, b, c;//ax+by=c
double x_min, x_max, y_min, y_max;//直线的值域
Line(const Point &first,const Point &second)
{
x_min = std::min(first.x, second.x);
x_max = std::max(first.x, second.x);
y_min = std::min(first.y, second.y);
y_max = std::max(first.y, second.y);
if (first.x != second.x)//斜率式可行
{
b = 1;
a = -(first.y - second.y) / (first.x - second.x);
c = first.y + a*first.x;
}
else//k->无穷
{
b = 0;
a = 1;
c = first.x;
}
}
bool lineParallel(const Line&line)//判断两直线是否平行
{
if (a*line.b - b*line.a==0)
{
return true;
}
return false;
}
bool lineOverlap(const Line&line)
{
auto D = a*line.b - line.a*b;
auto Dx = c*line.b - line.c*b;
auto Dy = a*line.c - line.a*c;
if (!D&&!Dx&&!Dy)
{
return true;
}
return false;
}
Point getIntersection(const Line&line)//行列式求两直线交点
{
auto D = a*line.b - line.a*b;
auto Dx = c*line.b - line.c*b;
auto Dy= a*line.c - line.a*c;
return{ Dx / D,Dy / D };
}
bool segmentIntersected(const Line &line)
{
auto point = getIntersection(line);
if (point.x >= x_min&&point.x <= x_max
&&point.y >= y_min&&point.y <= y_max
&&point.x >= line.x_min&&point.x <= line.x_max
&&point.y >= line.y_min&&point.y <= line.y_max
)//交点在两线段的值域内
{
return true;
}
return false;
}
};
class Rectangle
{
public:
int left, right, top, bottom;
bool inRectangle(const Point &point)
{
if (point.x >= left&&point.x <= right&&point.y >= bottom&&point.y <= top)
{
return true;
}
return false;
}
};
int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
cout << "INTERSECTING LINES OUTPUT" << endl;
int n;
while (cin >> n)
{
while (n--)
{
double x1, y1, x2, y2, x3, y3, x4, y4;
cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4;
Line line1({ x1,y1 }, { x2,y2 }), line2({ x3,y3 }, { x4,y4 });
if (line1.lineParallel(line2))
{
if (line1.lineOverlap(line2))
{
cout << "LINE" << endl;
}
else
{
cout << "NONE" << endl;
}
}
else
{
auto point = line1.getIntersection(line2);
cout << "POINT ";
printf("%.2lf %.2lf",point.x,point.y);
cout << endl;
}
}
}
cout << "END OF OUTPUT" << endl;
return 0;
}