POJ 1410

内部也是相交

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

struct point{
	int x,y;
};
struct edge{
	point start,end;
}line[4],the;

void swaped(int &x,int &y){
	int tmp=x;
	x=y;
	y=tmp;
}

int multi(point p1,point p2, point p0){
	return (p1.x-p0.x)*(p2.y-p0.y)-(p2.x-p0.x)*(p1.y-p0.y);
}

bool cross(edge v1, edge v2){
	if(max(v1.start.x,v1.end.x)>=min(v2.start.x,v2.end.x)&&
	max(v2.start.x,v2.end.x)>=min(v1.start.x,v1.end.x)&&
	max(v1.start.y,v1.end.y)>=min(v2.start.y,v2.end.y)&&
	max(v2.start.y,v2.end.y)>=min(v1.start.y,v1.end.y)&&
	multi(v2.start,v1.end,v1.start)*multi(v1.end,v2.end,v1.start)>=0&&
	multi(v1.start,v2.end,v2.start)*multi(v2.end,v1.end,v2.start)>=0)
	return true;
	return false;
}
/*
bool cross(point &a, point &b, point &c, point &d)
{
    if (min(a.x, b.x) > max(c.x, d.x) || min(a.y, b.y) > max(c.y, d.y) || min(
            c.x, d.x) > max(a.x, b.x) || min(c.y, d.y) > max(a.y, b.y))
        return 0;
    double h, i, j, k;
    h = (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
    i = (b.x - a.x) * (d.y - a.y) - (b.y - a.y) * (d.x - a.x);
    j = (d.x - c.x) * (a.y - c.y) - (d.y - c.y) * (a.x - c.x);
    k = (d.x - c.x) * (b.y - c.y) - (d.y - c.y) * (b.x - c.x);
    return h * i <= 0 && j * k <= 0;
}*/

int main(){
	int T; int xleft,ytop,xright,ybottom; int xstart,ystart,xend,yend;
	scanf("%d",&T);
	while(T--){
		scanf("%d%d%d%d%d%d%d%d",&xstart,&ystart,&xend,&yend,&xleft,&ytop,&xright,&ybottom);
		the.start.x=xstart; the.start.y=ystart;
		the.end.x=xend; the.end.y=yend;
		if(xleft>xright)
		swaped(xleft,xright);
		if(ytop<ybottom)
		swaped(ytop,ybottom);
		line[0].start.x=xleft; line[0].start.y=ytop;
		line[0].end.x=xright; line[0].end.y=ytop;
		line[1].start.x=xleft; line[1].start.y=ybottom;
		line[1].end.x=xright; line[1].end.y=ybottom;
		line[2].start.x=xleft; line[2].start.y=ybottom;
		line[2].end.x=xleft; line[2].end.y=ytop;
		line[3].start.x=xright; line[3].start.y=ybottom;
		line[3].end.x=xright; line[3].end.y=ytop;
		bool flag=true;
		for(int i=0;i<4;i++){
			if(cross(the,line[i])){
				flag=false;
				break;
			}
		}
		if(flag){
			if(xstart>=min(xleft,xright)&&xstart<=max(xleft,xright)&&
			   ystart>=min(ytop,ybottom)&&ystart<=max(ytop,ybottom)){
			   	flag=false;
			   }
   			else if(xend>=min(xleft,xright)&&xend<=max(xleft,xright)&&
			   yend>=min(ytop,ybottom)&&yend<=max(ytop,ybottom))
			   flag=false;
		}
		
		if(flag){
			printf("F\n");
		}
		else printf("T\n");
		
	}
	return 0;
}