View Code of Problem 67

#include<iostream>
using namespace std;
int main()
{
    double aX,aY,bX,bY,cX,cY,dX,dY,k1,k2,k3,k4;
    while(cin>>aX>>aY>>bX>>bY>>cX>>cY>>dX>>dY)
    {
        k1=(bY-aY)*(dX-cX);//相除转化为相乘
        k2=(dY-cY)*(bX-aX);

        k3=(dY-aY)*(bX-cX);//交换DB点
        k4=(bY-cY)*(dX-aX);


        if(k1==k2&&k3!=k4)cout<<"No"<<endl;

        else cout<<"Yes"<<endl;
    }
    return 0;
}