View Code of Problem 67

#include <stdio.h>
using namespace std;
int main(){
	
	float x1,x2,x3,x4;
	float y1,y2,y3,y4;
	double k1,k2;
	while( ~scanf("%f%f%f%f",&x1,&y1,&x2,&y2)){
		scanf("%f%f%f%f", &x3,&y3,&x4,&y4);
		if( x1 != x2 && x3 != x4 ){ //+
			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");
			}
		}else if( x1==x2 && x3==x4 && x1 != x3 ){
			printf("No\n");
		}else{
			printf("Yes\n");
		}
		
	}
	

	return 0;
	
}