Brute.java

import java.util.Arrays;

public class Brute {
    public static void main(String[] args) {

        // rescale coordinates and turn on animation mode
        StdDraw.setXscale(0, 32768);
        StdDraw.setYscale(0, 32768);
        StdDraw.show(0);

        // read in the input
        String filename = args[0];
        In in = new In(filename);
        int N = in.readInt();
        
        Point[] a = new Point[N];
        for (int i = 0; i < N; i++) {
            int x = in.readInt();
            int y = in.readInt();
            Point p = new Point(x, y);
            a[i] = p;
            p.draw();
        }

        Arrays.sort(a);
        
        for (int i = 0; i < N; i++)
            for (int j = i+1; j < N; j++)
                for (int k = j+1; k < N; k++)
                    for (int l = k+1; l < N; l++)
                        if (a[i].slopeTo(a[j]) == a[i].slopeTo(a[k])
                                && a[i].slopeTo(a[j]) == a[i].slopeTo(a[l])) {
                            StdOut.println(a[i].toString() + " -> "
                                    + a[j].toString() + " -> " + a[k].toString() 
                                    + " -> " + a[l].toString());
                            a[i].drawTo(a[l]);
                        }
        
        // display to screen all at once
        StdDraw.show(0);
    }
}