POJ-1410

#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string.h>
#include <cmath>
#define eps 1e-8
#define maxn 100
using namespace std;
int sgn(double x)
{
    if(abs(x) < eps) return 0;
    if(x<0) return -1;
    else return 1;
}
struct Point
{
    double x;
    double y;
    Point(){}
    Point(double _x,double _y)
    {
        x = _x;
        y = _y;
    }
    Point operator -(const Point &a) const
    {
        return Point(x-a.x,y-a.y);
    }
    Point operator + (const Point &a) const
    {
        return Point(x+a.x,y+a.y);
    }
    double  operator *(const Point &a) const
    {
        return x*a.x+y*a.y;
    }
    double  operator ^(const Point &a) const
    {
        return x*a.y-y*a.x;
    }
};
struct Line
{
    Point s;
    Point e;
    Line(){}
    Line(Point _s,Point _e)
    {
        s = _s;
        e = _e;
    }
};
///判断线段相交
bool inter(Line l1,Line l2)
{
    return
    max(l1.s.x,l1.e.x) >= min(l2.s.x,l2.e.x) &&
    max(l2.s.x,l2.e.x) >= min(l1.s.x,l1.e.x) &&
    max(l1.s.y,l1.e.y) >= min(l2.s.y,l2.e.y) &&
    max(l2.s.y,l2.e.y) >= min(l1.s.y,l1.e.y) &&
    sgn((l2.s-l1.e)^(l1.s-l1.e))*sgn((l2.e-l1.e)^(l1.s-l1.e)) <= 0&&
    sgn((l1.s-l2.e)^(l2.s-l2.e))*sgn((l1.e-l2.e)^(l2.s-l2.e)) <=0;
}
///判断直线和线段是否相交
bool seg_inter_line(Line l1,Line l2)
{
    return sgn((l2.s-l1.e)^(l1.s-l1.e))*sgn((l2.e-l1.e)^(l1.s,l1.e)) <=0;
}
bool Onseg(Point p,Line L)
{
    return
    sgn((L.s-p)^(L.e-p)) == 0 &&
    sgn((p.x-L.s.x)*(p.x-L.e.x)) <= 0 &&
    sgn((p.y-L.s.y)*(p.y-L.e.y)) <= 0;
}
int inConvexpoly(Point a,Point p[],int n)
{
    for(int i=0;i<n;i++)
    {
        if(sgn((p[i]-a)^(p[(i+1)%n]-a)) < 0) return -1;
        else if(Onseg(a,Line(p[i],p[(i+1)%n]))) return 0;
    }
    return 1;
}
int main()
{
    //freopen("in.txt","r",stdin);
    int T;
    scanf("%d",&T);
    while(T--)
    {
        Point s;
        Point e;
        double  x1,y1,x2,y2;
        scanf("%lf %lf %lf %lf %lf %lf %lf %lf",&s.x,&s.y,&e.x,&e.y,&x1,&y1,&x2,&y2);
        if(x1 > x2) swap(x1,x2);
        if(y1 > y2) swap(y1,y2);
        Point p[10];
        Line L = Line(s,e);
        p[0] = Point(x1,y1);
        p[1] = Point(x2,y1);
        p[2] = Point(x2,y2);
        p[3] = Point(x1,y2);
        if(inter(L,Line(p[0],p[1])))
        {
            printf("T\n");
            continue;
        }
        else if(inter(L,Line(p[1],p[2])))
        {
            printf("T\n");
            continue;
        }
        else if(inter(L,Line(p[2],p[3])))
        {
            printf("T\n");
            continue;
        }
        else if(inter(L,Line(p[3],p[0])))
        {
            printf("T\n");
            continue;
        }
        else if(inConvexpoly(L.s,p,4)>=0 || inConvexpoly(L.e,p,4)>=0)
        {
             printf("T\n");
            continue;
        }
        else
            printf("F\n");
    }
    return 0;
}