View Code of Problem 67

#include <stdio.h>
using namespace std;
int main() {
    double x1,x2,x3,x4,y1,y2,y3,y4,k1,k2;
    while(~scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2)){
       scanf("%lf%lf%lf%lf",&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;
}