View Code of Problem 67

#include<stdio.h> 
#include<string.h>
#include<math.h>
int main(){ 
    int x1,y1,x2,y2,x3,y3,x4,y4;
    float k1,k2;
    while(~scanf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4)){
    	
    	if(x1==x2&&x3==x4){
    		if(x1==x3) printf("Yes\n");
    		else printf("No\n");
		}
		else if(x1==x2||x3==x4) printf("Yes\n");
		else{
			k1=1.0*(y2-y1)/(x2-x1);
    	    k2=1.0*(y4-y3)/(x4-x3);
			if(k1!=k2) printf("Yes\n");
			else if(y1-k1*x1!=y3-k2*x3) printf("No\n");
			else printf("Yes\n");
		}
	}
    return 0; 
     
}