View Code of Problem 67

#include <stdio.h>
#include <string.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");
		  }
	}
	return 0;
}