View Code of Problem 67

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