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/* vim: set expandtab tabstop=4 shiftwidth=4 : */
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;
public class Fast
{
static class Segment
{
private Point[] pts;
public Segment(Point ref, Point[] origin, int start, int n)
{
this.pts = new Point[n];
int i = 0;
int j = start;
boolean inserted = false;
while (i < (n - 1))
{
if (!inserted && (ref.compareTo(origin[j]) < 0))
{
pts[i++] = ref;
pts[i] = origin[j++];
inserted = true;
}
else
pts[i] = origin[j++];
i++;
}
if (!inserted)
pts[n - 1] = ref;
else
pts[n - 1] = origin[start + n - 2];
}
public boolean equals(Object other)
{
if (other == this) return true;
if (other == null) return false;
if (other.getClass() != this.getClass()) return false;
Segment s = (Segment) other;
if ((pts[0].compareTo(s.pts[0]) == 0)
|| (pts[pts.length - 1].compareTo(s.pts[s.pts.length - 1]) == 0))
return true;
return false;
}
public void draw()
{
pts[0].drawTo(pts[pts.length-1]);
}
public void print()
{
String out = "";
for (Point p : pts)
out += p+" -> ";
StdOut.println(out.substring(0, (out.length() - 4)));
}
}
static List<Segment> solve(Point[] pts, int N)
{
List<Segment> segments = new ArrayList<Segment>();
for (int i = 0; i < N - 1; i++)
{
int n = N - i - 1;
Point ref = pts[i];
Point[] others = new Point[n];
for (int j = 0, k = i + 1; j < n; j++, k++)
others[j] = pts[k];
Arrays.sort(others, ref.SLOPE_ORDER);
int start = -1;
double slope = Double.NEGATIVE_INFINITY;
for (int j = 0; j < n; j++)
{
double sl = ref.slopeTo(others[j]);
if (sl == Double.NEGATIVE_INFINITY)
continue;
if (slope != sl)
{
if ((start != -1) && ((j - start) > 2))
{
Segment seg = new Segment(ref, others,
start, (j - start + 1));
if (!segments.contains(seg))
segments.add(seg);
}
slope = sl;
start = j;
}
}
if ((n - start) > 2)
{
Segment seg = new Segment(ref, others, start, (n - start + 1));
if (!segments.contains(seg))
segments.add(seg);
}
}
return segments;
}
public static void main(String[] args)
{
In in = new In(args[0]);
int n = in.readInt();
StdDraw.setXscale(0, 32768);
StdDraw.setYscale(0, 32768);
StdDraw.show(0);
Point[] pts = new Point[n];
for (int i = 0; i < n; i++)
{
pts[i] = new Point(in.readInt(), in.readInt());
pts[i].draw();
}
Arrays.sort(pts);
// Stopwatch w = new Stopwatch();
for (Segment sol : solve(pts, n))
{
sol.draw();
sol.print();
}
// StdOut.printf("Time: %f\n\n", w.elapsedTime());
StdDraw.show(0);
}
}
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