AOJ Volume0-0021

http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0021&lang=jp

#include <iostream>
#include <string>
using namespace std;

int main (int argc, const char * argv[])
{
    double read;
    int set;
    double x[4],y[4];
    
    cin >> set;
    
    for (int i=0; i < set; i++) {
        int count = 0;
        for (int j=0; j < 8; j++) {
            cin >> read;
            if (j % 2 == 0) {
                x[count] = read;
            }else {
                y[count] = read;
                count++;
            }
        }
        double a = (y[0] - y[1]) / (x[0] - x[1]);
        double b = (y[2] - y[3]) / (x[2] - x[3]);
        if (a == b) {
            cout << "YES\n";
        }else {
            cout << "NO\n";
        }
    }
    return 0;
}