Priority Queue In Java Which Keeps Track Of Each Node Position
May 4, 2014
I'm working on a lab for my class. I need to create a Priority Queue in Java using an array list. The kicker is that each node has to have a "handle" which is just an object which contains the index of of the node that it's associated with. I know that sounds weird but we have to implement it this way. Anyway, my priority queue seem to work fine except the handle values apparently aren't updating correctly because I fail the handle test. Also, I run into problems with handles only after extractMin() is called, so I figured the problem would be somewhere in that method but I've been through it a million times and it looks good to me.
Here is my Priority Queue Class:
package lab3;
import java.util.ArrayList;
/**
* A priority queue class supporting operations needed for
* Dijkstra's algorithm.
*/
class PriorityQueue<T> {
final static int INF = 1000000000;
ArrayList<PQNode<T>> queue;
[Code] ....
I can post the tests too but I don't know if that would do much good. Just know that the queue works as is should, but the handles don't point to the right nodes after extractMin() is utilized.
I have a class "ExecuteJob" which has Print Q in the form of Priority Q.
You can keep adding job to the Q by calling one of the method in the class. However, and object cant do things simultaneity can it? While im adding a new job to the print queue, can it be executing and existing job in the print Q.
To achieve that, I would need to implement process and threads? I believe am I right? So that adding a job is independent to being removed?
I am in the process of implementing Priority queue, as I understand that there are many data structures you could use to implement. I implemented it with the an array, which it works absolutely fine. However I have limitations on what collections I can use from the collections classes. I fact I cant use any of the collections classes. Meaning I cant use array.
I’m trying to implement Priority Queue using heap. And implementing heap using binary trees. But however I have a few questions which I need to clarify and I cant think of any other way of resolving it. Ofcourse I can implement my own simple array class using linked list.
Inserting into heap would be quite simple, as I just need to find the right last position from left to right leaf to insert the node into the tree. However after inserting, you may want to make sure that leaf node values are > than root node. Therefore, the root node will always be with the highest priority.
I call these steps where you compare from top down as bubbledown and bubbleup. To do this I really need a for each node within the treee node to have attribute pointing to its root node. So in case of bubbleup I always have a pointer for a given node to its root, without it would mean I would to traverse through the entire tree to identify its root. Which I believe is very inefficient.
Or have I taken this completely wrong? Or is it the case that heap are only best with arrays and therefore use array (by implement it using linked list?)
I am working on a program that asks me to track the position of an imaginary ball as it bounces around an imaginary box. The user gives me input for the starting position of the ball (x,y), the bottom-left boundaries of the box (xl, yl), the top right boundaries (xr, yr) and the angle. The program then needs to find where the ball will hit the box, and then print that location and find the new angle for the next point. My program currently works in most cases if the angle is less than pi.
Here is my code
public class BouncyBall { public static void main(String args[]){ if (args.length != 8) { System.out.println("Error: usage is X, Y, Angle, Xl, Yl, Xr, Yr,N"); System.exit(1); } double x,y,xl,yl,xr,yr,angle; int n; x=Double.parseDouble(args[0]); y=Double.parseDouble(args[1]);
My assignment was to create a priority queue for Airline Passengers. Here is what I have done so far:
//Driver
package priorityqueuestandby; import java.util.NoSuchElementException; import javax.swing.JOptionPane; public class PriorityQueueStandBy { public static void main(String[] args) {
[Code] .....
So the part that I cant figure out is:
When a standby passenger is to be enqueued into the priority queue, it must be done so that at the moment of each dequeue operation, the item at the head of the queue is the standby passenger with the longest longevity, and also so that passengers with the same longevity are dequeued in a first-come-first-served fashion.
he says that we need to "Make your program so that it extends Comparable and implements the compareTo() method properly..."
So I was looking at the Comparable class and I could't find a compareTo() method... I am not confident I know how extends works either. I am assuming I need a new class if I am going to be extending another class. Right now I am taking in longevity as a String and converting it to an int because my last ditch effort is going to be to set up a loop that will organize longevity into a/an circular array based on the size of the incoming integer.
I was given some code by a professor to add some features to as part of an assignment. However, the code itself doesn't seem to work.
import java.util.HashSet; import java.util.InputMismatchException; import java.util.PriorityQueue; import java.util.Scanner; import java.util.Set; public class DijkstraPriorityQueue
[Code] ....
The method to find minimum distance is nonfunctional...I receive an error that the types are incompatible. I can't do the assignment if the base code doesn't work to begin with...
I am trying to design a monopoly board game with a class and a main program. I can not make the method to keep track of the player's position after every roll. After every roll it prints "Previous position: 0".The player should also not go over 14th spot because the board is just 15 including 0. That is what I have (just the particular method and the part from the main program which call it).
public int getpospl1() { System.out.println( getplayer1name() + " Rolls " + "Dice 1: " + getrolld1() + "" + "Dice 2: " + getrolld2() + "" ); int spot1 = 14; //The end spot int start = 0; int previousPosition = start;
I want to ask if there is an option to set the vertical position of the node handles of the TreeView-control.
I used a custom TreeCell factory with icons of sizes between 24 and 64 pixel and the location of the handle is regardless of the size of the icon on top of the cell. So if you got large icons the view did not look so nice.What I want is a property or something to center the handle in the cell depending on the size of the cell. Is there such an option?
I need to make a program that keeps track of peoples names, allows you to add a note to each name and preferably would reorganize whatever you put in by date or by spelling. (I suppose the phonebook application in cell phones is a good match, a supermarket's list of foods and prices would work as well).
I have an assignment in which I have to design a method where I add an object at any given position in an array and shift the elements already in the array to make room. For example I have a collection class which holds trading card objects. So I wish to add a new trading card to this collection at a specified index or position with out deleting the current object already stored in the array . All this has to be done without the use of array lists, vectors or any abstract data types besides arrays . My question is how do I accomplish this . Say I wish to add a new trading card in position 4 the new card is added to my array and the card currently in position 4 gets moved to position 5 and the card in position 5 gets moved to 6 etc. The maximum amount of cards my collection can hold is 100. How would I add my trading card object to the specified position without overwriting what is currently there and shifting all other elements?Here is my current code.
public class CardCollection { public BaseballCard [] collection; final int MAX_CARDS = 100; public CardCollection() { collection = new BaseballCard[MAX_CARDS]; } public CardCollection(BaseballCard[]c)
[code]...
position refers to the position in the CardCollection and not the position inside the array.
I have a Queue class (containing a LinkedList plus a few other variables and stats for my project), which works fine with the standard LinkedList, but I'm trying to add my own code for MyLinkedList.
However, I keep getting a NullPointerException at my remove method.
public class MyLinkedList<T> { Node head; public MyLinkedList() { head = null; } public class Node { T contents; Node nextNode;
I have an assignment to complete where I have to develop a Java Console application in Eclipse which accepts regional zone information for premises based upon addresses provided. The program needs to figure out which geographical zone each customer lives in and based upon their age, set a priority rating.
The zones (which is the Belfast and the directions) and sub-zones (which are the Postcode such as "BT1" are:
1.Display a count of addresses within a user defined geographical zone. 2.Display all information for customers within a user defined geographical zone. 3.Display a complete set of captured data. 4.Display a prioritized list of customer details within each geographical zone. 5.Display a count of customers within each geographical zone.
Below is the code I have created so far for it.
package assignment1;
import java.io.BufferedReader; import java.io.InputStreamReader; public class Assignment1 { private static InputStreamReader input = new InputStreamReader(System.in); private static BufferedReader reader = new BufferedReader(input);
[Code] .....
The main issue I'm having is to make sure that data like address and customer counts, and customer details appear only for the selected areas.
So I have a player an enemy and enemy bounds the enemy can go. I need to have the enemy track my position and when I go into the position (I am using a collision method for this) the enemy comes over at a speed of 1. My problem is the enemy jumps to me and then follows at speed of 2 (2 is the player speed). The code is wrong this is why it is jumping and I have my other problems. so my question is what is a good solution for this? I am trying to make a method to track playerposition() so what I am thinking I could do is find x, y of player then store those into an array and return the array to Enemy so he tracks.
player.java public class Player{ int x = 100; // Location of player int y = 200; // location of player int xa = 0; // Representation of where the player goes int ya = 0; // Representation of where the player goes private int speed = 2;
[Code] .....
Please note this is not the entire code I have cut some things out that did not need to be there. Also, the code is just to get an idea of what I was thinking of doing. The ideas that are came up with are not meant to be a reflection of what I already have but, what I could add or replace.
I'm trying to make a canteen class that holds water. It holds two quarts of water and two quarts is 100%.
public double maxVolume; public int percentFull;
Right now the Canteen is empty.
public void Canteen() { percentFull=0; maxVolume=0; }
And right now I'm trying to make a constructor that specifies the amount of liquid the canteen can hold and specifies the percent full.
public Canteen(double maxVolume, int percentFull) { }
Should I make this second Canteen an integer, a double, or something else? Also, how do I make sure the Canteen never reaches higher than 100%. I'm also curious how I can keep maxVolume and percentFull connected so the % of water is consistent with the number of quarts(2) the Canteen can hold.
I have two JFrames: frame1 and frame2. frame2 currently has focus, and I want to determine which component of frame1 would have focus if I were to switch focus to frame1, hopefully without actually temporarily changing focus.
Is it the KeyboardFocusManager who keeps track of which element in each frame has focus? Or does each container itself keep track? How does Java figure out which element in a frame gets focus when I switch to that window?
Which is the best way to keep track of the number of the objects I've created?Is is a good practice to have a static variable, which will be incremented everytime I call a contructor?
The code I have below asks the user how many times you want to roll the dice. It rolls dice 1 and dice 2 randomly and gives the total. Now, I'm trying to keep track of the result of each roll using an array that is indexed by the sum of the roll of the two dice. Then I want to output my result in a table that shows each value (from 2 - 12)) and the number of times that value was rolled. I would like to do this preferably with the JTextArea class, but it doesn't have to be. I keep getting errors.The code below works for the dice rolling in the 1st paragraph. I took out all the bad code I was trying to use for the 2nd paragraph.
package Part2pack; import java.util.Random; import javax.swing.JOptionPane; class Dice{ public static void main (String args[]) { String input = " "; int count = 0,dice1,dice2;
Basically we have to create a calculator that it will have to keep track of the current value, and do the functions that the calculator uses.
But I have it working for the most part, but the current value does not keep...
The double " currentValue " Must stay private.
import java.util.*; public class MemoryCaluclator { private double currentValue; public static void main(String[] args) { Scanner stdIn = new Scanner(System.in); int answer = 0;
I am currently truing to make this class instantiate 100,000 dice rolls of 2 dice. And I also need to keep track of how many times each possible total occurs and I am having trouble outputting the result. Right now when I run my code it is just showing the results of each of the 100,000 roles.
public class ltefera_DiceRollTest { public static void main(String[] args) { ltefera_DiceRoll diceRoll = new ltefera_DiceRoll(10); System.out.println("Total # of pips" + " "); diceRoll.printArray(); System.out.println(diceRoll.countDice(2)); System.out.println(diceRoll.isArrayDataValid()); System.out.println(diceRoll.getTotal()); System.out.println(diceRoll.allDifferent());
Here are my conditions: You are developing a program to keep track of team standings in a league. When a game is played, the winning team (the team with the higher score) gets 2 points and the losing team gets no points. If there is a tie, both teams get 1 point. The order of the standings must be adjusted whenever the results of a game between two teams are reported. The following class records the results of one game.
public class GameResult { public String homeTeam() // name of home team { /* code not shown */ }
public String awayTeam() // name of away team
[Code] ....
The class TeamStandings stores information on the team standings. A partial declaration is shown below.
public class TeamStandings { TeamInfo[] standings; // maintained in decreasing order by points, // teams with equal points can be in any order public void recordGameResult(GameResult result)
[Code] ....
And here is the actual question:
Write the method adjust. The method adjust should increment the team points for the team found at the index position in standings by the amount given by the parameter points. In addition, the position of the team found at index in standings should be changed to maintain standings in decreasing order by points; teams for which points are equal can appear in any order.
And here is what I have so far:
private void adjust(int index, int points) { int Score[] = new int[standings.length] for ( int i=0; i <= standings.length; i++) { Score[i] = index, points; } }
I've built up an unreasonably large and unreasonably complicated JPanel. Unfortunately, when I use setViewportView to add it to a JScrollPane, a get an extended UI freeze—that operation takes several seconds. I'm trying to figure out what's taking so long. I've tried some fairly extreme things, like overriding the paintComponent, PaintComponents, paintChildren, paint, repaint, validate, revalidate, and validateTree methods in the panel with no-ops to try to figure out what's taking so long, but to no avail. I've tried validating the JPanel before adding it, but that has no effect. If I override the addImpl method of the scroll pane, that makes things quick, but it doesn't really narrow things down much.
