View Code of Problem 67

#include <iostream>
#include <cstdio>
using namespace std;
int main(){
    double x1 , x2 , x3 , x4;
    double y1 , y2 , y3 , y4;
    double k1 , k2 , b1 , b2;
    while(cin>>x1>>y1>>x2>>y2>>x3>>y3>>x4>>y4){
        if(x1 != x2 && x3 != x4){
            k1 = ( y1 - y2 ) / ( x1 - x2 );
            k2 = ( y3 - y4 ) / ( x3 - x4 );
            b1 = y1 - k1 * x1;
            b2 = y3 - k2 * x3;
            if(k1 == k2 && b1 != b2)
                cout<<"No"<<endl;
            else
                cout<<"Yes"<<endl;
        }
        else if(x1 == x2 && x3 == x4){
            if(x1 == x3)
                cout<<"Yes"<<endl;
            else
                cout<<"No"<<endl;
        }
        else cout<<"Yes"<<endl;
    }
    return 0;
}