View Code of Problem 67

#include<stdio.h>
int main()
{
	int x1,y1,x2,y2,x3,y3,x4,y4;
	while(scanf("%d %d %d %d",&x1,&y1,&x2,&y2)!=EOF)
	{
	scanf("%d %d %d %d",&x3,&y3,&x4,&y4);
	
	int a=(y2-y1)*(x4-x3);
	int b=(y4-y3)*(x2-x1);//如果k1=k2,说明两条线平行或者重合 
	
	int c=(y3-y1)*(x2-x1);
 	int d=(y2-y1)*(x3-x1);
	if(a==b&&c!=d)
		printf("No\n");
	else printf("Yes\n");		
	}
	return 0;
}