View Code of Problem 67

#include<bits/stdc++.h>
using namespace std;
int main() {
	int x1, x2, y1, y2, x3, y3, x4, y4;
	while (cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3 >> x4 >> y4) {
		//相交
		int f1 = (x1 - x2)*(y1 - y2);
		int f2 = (x3 - x4)*(y3 - y4);
		//重合
		int f3 = (y4 - y1)*(x2 - x3);
		int f4 = (y2 - y3)*(x4 - x1);
		if (f1 == f2 && f3 != f4) {
			cout << "No" << endl;
		}
		else {
			cout << "Yes" << endl;
		}
	}

	return 0;
}