// ================================ main ===============================
//
// You can use command line arguments to have the output and/or input
// come from a file versus the command line.
//
// If there are two arguments then the first one is the file from where
// the input is read and the second is the file where a transcript is
// saved.
//
// If there is just one argument then it is the file where a transcript
// is saved.
public static void main(String args[]) {
XYPoint points[];
if (args.length >= 1) {
Terminal.startTranscript(args[0]);
}
if (args.length >= 2) {
// Read points from file
points = PointReader.readXYPoints(args[1]);
} else {
// You can change "" to something else when testing,
// but it MUST be "3861" for your submitted output!
java.util.Random randseq = new java.util.Random(3861);
// Use this line if you want a different random set of
// points for each run. This code uses the system
// clock as the seed to the random number generator.
//
// java.util.Random randseq = new java.util.Random();
Terminal.println("How many points? ");
int nPoints = Terminal.readInt();
points = genPointsAtRandom(nPoints, randseq);
}
XComparator lessThanX = new XComparator();
YComparator lessThanY = new YComparator();
Date startTime = new Date();
//////////////////////////////////////////////////////////////////////
// CLOSEST-PAIR ALGORITHM STARTS HERE
// The algorithm expects two arrays containing the same points.
XYPoint pointsByX[] = new XYPoint[points.length];
XYPoint pointsByY[] = new XYPoint[points.length];
for (int j = 0; j < points.length; j++) {
pointsByX[j] = points[j];
pointsByY[j] = points[j];
}
// Ensure sorting precondition for divide-and-conquer CP algorithm.
// You should *not* have to call msort() in your own code!
Sort.msort(pointsByX, lessThanX); // sort by x-coord
Sort.msort(pointsByY, lessThanY); // sort by y-coord
Result rMin = ClosestPair.findClosestPair(pointsByX, pointsByY);
rMin.print();
// CLOSEST-PAIR ALGORITHM ENDS HERE
//////////////////////////////////////////////////////////////////////
Date endTime = new Date();
long elapsedTime = endTime.getTime() - startTime.getTime();
Terminal.println(
"For n = " + points.length + ", the elapsed time is " + elapsedTime + " milliseconds.\n");
// *** NOTE: for your submitted output for Part Two, you MUST print
// *** the closest pair of points and the distance between them!
//////////////////////////////////////////////////////////////////////
// THE FOLLOWING LINES DEMONSTRATE HOW TO USE THE PROVIDED
// PLOTTER ROUTINE. Uncomment them as you wish for debugging
// purposes, or use them in your closest pair code to inspect
// the point arrays at any time. For example, you could color
// all points in the left half red and all points in the right
// half blue and then visually check that you divided them
// properly by calling the plotter before you recurse. Note
// that if you make several calls, all the plots will
// initially be on top of each other -- just move them so you
// can see everything.
//
// Here the points are plotted and labelled by X-coordinate
// new Plotter(pointsByY, true, "Sorted by X-coordinate");
// Here the points are plotted and labelled by Y-coordinate
// new Plotter(pointsByY, true, "Sorted by Y-coordinate");
// Here's a call to the plot routine in which the points
// aren't labeled. A nice thing to do at this point (if you
// computed the two closest points) would be to color the two
// closest points a different color For a XYPoint p, you could
// color p (say red) with the line:
//
// p.color = Color.red;
// new Plotter(pointsByX, true, "Output");
}
