View Code of Problem 67

#include<stdio.h>
#include<math.h>
int main()
{
	float x1,x2,x3,x4,y1,y2,y3,y4,k1,k2,b1,b2;
	while(scanf("%f %f %f %f %f %f %f %f",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4)!=EOF)
	{
		if(x1==x2&&x3==x4)
		{
			if(x1==x3)
				printf("Yes\n");
			else
				printf("No\n");
		}
		else
		{
		k1=(y1-y2)/(x1-x2);
		k2=(y3-y4)/(x3-x4);
		b1=y1-k1*x1;
		b2=y3-k2*x3;
		if(k1==k2&&b1!=b2)
			printf("No\n");
		else
			printf("Yes\n");
		}
	}
}