line segment intersection

#include <stdio.h>
#include <math.h>
int main(void)
{
	long long int x1,x2,x3,x4,y1,y2,y3,y4;
	int t;
	scanf("%d",&t);
	while(t!=0)
	{
		t--;
		scanf("%lld %lld %lld %lld %lld %lld %lld %lld",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4);
		double s =0;
		double t =0;
		if(((x2-x1)*(y3-y4) - (y2-y1)*(x3-x4)) != 0)
	        {
			double s = -1*((double)((x3-x4)*(y3-y1))-((y3-y4)*(x3-x1)))/((x2-x1)*(y3-y4) - (y2-y1)*(x3-x4));
			double t= ((double)((x2-x1)*(y3-y1) - ((y2-y1)*(x3-x1))))/((x2-x1)*(y3-y4) - (y2-y1)*(x3-x4));
			if(s>=0 && s<=1 && t>=0 && t<=1)
				printf("Yes\n");
			else
				printf("No\n");
		}
		else 
		{
			if((x3-x4)*(y3-y1) - (y3-y4)*(x3-x1) == 0 || (x2-x1)*(y3-y1) - (y2-y1)*(x3-x1)==0)
			{
				if((x1<=x3 && x1>=x4) || (x1<=x4 && x1>=x3) || (x2<=x3 && x2>=x4) || (x2<=x4 && x2>=x3) || (x1<=x3 && x1<=x4 && x2>=x3 && x2>=x4) || (x2<=x3 && x2<=x4 && x2>=x3 && x2>=x4))
				{
				if((y1<=y3 && y1>=y4) || (y1<=y4 && y1>=y3) || (y2<=y3 && y2>=y4) || (y2<=y4 && y2>=y3))
                                {
                                        printf("Yes\n");
                                        continue;
                                }
                                else if((y1<=y3 && y2<=y3 && y1>=y4 && y2>=y4) || (y1<=y4 && y2<=y4 && y2>=y3 && y2>=y3) || (y1<=y3 && y1<=y4 && y2>=y3 && y2>=y4 ) || (y2<=y3 && y2<=y4 && y1>=y3 && y1>=y4))
                                {
                                        printf("Yes\n");
                                        continue;
                                }
				}
				printf("No\n");
				
			}

			else
				printf("No\n");
		}
	}
	return 0;
}