Welcome to the Java Programming Forums


The professional, friendly Java community. 21,500 members and growing!


The Java Programming Forums are a community of Java programmers from all around the World. Our members have a wide range of skills and they all have one thing in common: A passion to learn and code Java. We invite beginner Java programmers right through to Java professionals to post here and share your knowledge. Become a part of the community, help others, expand your knowledge of Java and enjoy talking with like minded people. Registration is quick and best of all free. We look forward to meeting you.


>> REGISTER NOW TO START POSTING


Members have full access to the forums. Advertisements are removed for registered users.

Results 1 to 4 of 4

Thread: Help with Schedule Generator

  1. #1
    Junior Member
    Join Date
    Feb 2013
    Posts
    10
    Thanks
    1
    Thanked 0 Times in 0 Posts

    Default Help with Schedule Generator

    This is a recreational project for my fantasy football league. I will try to very thoroughly explain my thinking and what I have done so far.
    I'm trying to create a random schedule generator. But the problem is there are a lot of conditions that need to be met and whenever I try to implement some of these restrictions it causes infinite loops, which in my opinion, should not be happening. I could just be thinking wrong, or it could be the random number generator.

    It is a ten team league and a 13 week season. Every team plays the other nine teams one time. Then each team plays 4 teams twice. What I have done is created an array list of every possible matchup by assigning an id to each team with numbers ranging from 21 to 30 (I chose this because it will create a unique matchup id when any two of the numbers are 21 to 30 are multiplied together). Every team is in an array list called teams. So I did this to create all the unique matchups:

    		ArrayList<Matchups> defMatchups = new ArrayList<Matchups>();
    		for(i = 0; i < 10; i++){
    			for(j = i + 1; j < 10; j++){
    				defMatchups.add(new Matchups(teams.get(i), teams.get(j)));
    			}
    This works every time and is not the problem. The problem comes when I try to randomly generate the 4 duplicate matchups for each team. My function to do this is as follows:
    package helpers;
     
    import java.util.ArrayList;
    import java.util.Iterator;
    import java.util.Random;
     
    import matchups.Matchups;
    import teams.Teams;
     
    public class RandomizeSecondMatchups {
    	public static ArrayList<Matchups> run(ArrayList<Matchups> original){
    		ArrayList<Matchups> list = new ArrayList<Matchups>();
    		ArrayList<Matchups> copy = new ArrayList<Matchups>();
    		Iterator<Matchups> it = original.iterator();
    		Matchups current;
    		while(it.hasNext()){
    			current = it.next();
    			copy.add(current);
    		}
    		int counter = 0;
    		Random rand = new Random();
    		Teams temp1, temp2;
    		Matchups tempMU;
    		do{
    [B]			do{
    			tempMU = copy.get(rand.nextInt(copy.size()));
    			System.out.println("--");
    			}while(tempMU.getTeamOne().getCount() >=4 || tempMU.getTeamTwo().getCount() >= 4 );[/B]
    			temp1 = tempMU.getTeamOne();
    			temp2 = tempMU.getTeamTwo();
    			temp1.incCount();
    			if(temp1.getCount() == 4){ counter++; }
    			temp2.incCount();
    			if(temp2.getCount() == 4){ counter++; }
    			list.add(tempMU);
    			copy.remove(tempMU);
     
    		}while(counter < 10);
    		return list;
    	}
    }

    An infinite loop usually occurs in the bolded section (the do while loop with the bold tags around it). But there are a few times (about once every 4 or 5 times) where it does not infinite loop and it executes exactly how I want. Which is making me think that my random number is the problem or possibly even eclipse. I have gotten farther into the program and know I will experience more infinite looping problems later on as I will be adding more restrictions in, (e.g. matchups can't repeat themselves in consecutive weeks), so I would like to get this one to work perfectly before I move on.

    Anything you can do to help me out be greatly appreciated. If you need to see other classes in my code to help me out let me know, and I will post it up.


  2. #2
    Super Moderator Norm's Avatar
    Join Date
    May 2010
    Location
    SW Missouri
    Posts
    20,620
    Thanks
    50
    Thanked 2,235 Times in 2,207 Posts

    Default Re: Help with Schedule Generator

    An infinite loop usually occurs
    What keeps the code going around the loop? Is there a variable whose value needs to change to allow the loop to exit and the code is not changing the variable's value?

    Try debugging the code by adding some println statements to print out the values of the variables that control the loop so you can see how its value is changing (or not) and understand why there is the long looping.
    If you don't understand my answer, don't ignore it, ask a question.

  3. The Following User Says Thank You to Norm For This Useful Post:

    popnfresh (April 9th, 2013)

  4. #3
    Junior Member
    Join Date
    Feb 2013
    Posts
    10
    Thanks
    1
    Thanked 0 Times in 0 Posts

    Default Re: Help with Schedule Generator

    Quote Originally Posted by Norm View Post
    What keeps the code going around the loop? Is there a variable whose value needs to change to allow the loop to exit and the code is not changing the variable's value?

    Try debugging the code by adding some println statements to print out the values of the variables that control the loop so you can see how its value is changing (or not) and understand why there is the long looping.
    The loop occurs where I thought it was happening.
    I figured out that it happens when only two teams have a count of 3 left, but those two teams have already played each other twice, meaning that they cannot play each other for a third time. Which means I have some thinking to do. If you can think of a fix I would be forever grateful. I've been working on this for quite some time(originally in C, I just started in java). There was also a case where 9 teams would have count of 4 and one team would have a count of 2. Not sure how that happened

  5. #4
    Super Moderator Norm's Avatar
    Join Date
    May 2010
    Location
    SW Missouri
    Posts
    20,620
    Thanks
    50
    Thanked 2,235 Times in 2,207 Posts

    Default Re: Help with Schedule Generator

    Sounds like you need to do some thinking and make a design that will handle the cases.
    If you don't understand my answer, don't ignore it, ask a question.

Similar Threads

  1. Amortization Schedule Table Help.
    By pj6444 in forum AWT / Java Swing
    Replies: 2
    Last Post: January 6th, 2013, 07:58 PM
  2. [SOLVED] Need Help Generating Loan Repayment Schedule
    By C++kingKnowledge in forum What's Wrong With My Code?
    Replies: 4
    Last Post: November 3rd, 2012, 01:11 PM
  3. How to schedule this to happen daily?
    By dynamix24 in forum What's Wrong With My Code?
    Replies: 1
    Last Post: October 25th, 2012, 06:19 PM
  4. Timer.schedule
    By johnboyofsj in forum Java Theory & Questions
    Replies: 1
    Last Post: October 14th, 2012, 10:02 PM
  5. Replies: 0
    Last Post: January 25th, 2011, 12:24 AM