Trees in Java

Hi All,
I am looking for ways to store data in the database in Binary Tree format and then retrieve and display the data in Tree format in JSP. There are lots of topic on JTree. But this requires the construction of Tree. I want to store the data itself as Tree and then display it. Could anyone offer help ?
Thanks in advance.

for example if i enter a new
value all i need to specify is its parent.Hi again,
hmm ... that is not the way, a binary tree works - a binary tree should garantee that both branches are of nearly equal size - that is called a balanced tree - only when it is balanced you get the efforts of binary search in the tree, good performance - find a value in less than 1+log n steps if log means the logarithmic function based on 2 ( sorry, I am German and don't know the correct english term for it) and n means the number of nodes in the tree.
So, when you insert a new value in that tree, the algorithmus chooses the place in that tree, not the user. And the tree must be rearranged to keep the balance so that the performance of that tree can be garanteed. In many cases this means that the first position of a value in the tree will be changed by the rebalancing operations needed.
Thinik this over
greetings Marsian

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quote:
Originally posted by:
ntsiii
Stop running and get a map (read the documents)
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Creating non binary trees in Java

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Hi,
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Non binary trees in java

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public class Node {
private final Object payload;
private final Set<Node> children;
public Node(Object payload) {
this.payload = payload;
children = new HashSet<Node>();
// now add methods to add/remove children, a method to do something with the payload (say,
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Binary Tree in Java - ******URGENT********

HI,
i want to represent a binary tree in java. is there any way of doing that.
thanx
sraphson

HI,
i want to represent a binary tree in java. is there
e any way of doing that.
thanx
sraphsonFirst, what is a binary tree? Do you know how the binary tree looks like on puesdo code? How about a representation in terms of numbers? What is a tree? What is binary? The reason I ask is, what do you know about programming?
Asking to represent a binary tree in java seems like a question who doesn't know how it looks like in the first please. Believe me, I am one of them. I am not at this level yet. If you are taking a class that is teaching binary trees and you don't know how it looks like, go back to your notes.
Sounds harsh, but it is better to hear it from a person that doesn't know either then a boss that hired you because Computer Science was what you degree said. Yet, you don't know how to program?
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http://java.sun.com/docs/books/tutorial/uiswing/components/tree.html
CS312 Data Structures and Analysis of Algorithms
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Binary trees in Java

Hi there
Do you have any suggestions about how to implement trees or binary trees in Java?
As far as I know there are already some libraries for that, but I don't know how to use them. Was trying to get some implementation examples but I'm still very confused.
How can I use for example:
removeChild(Tree t)
addChild(Tree t)
isLeaf()
Thanks in advance

Lulu wrote:
Hi there
I have several questions about binary trees
Let's see, I use TreeMap to create them with the following code:
TreeMap treeMap = new TreeMap<Integer, String>();
treeMap.put("first", "Fruit");
treeMap.put("second","Orange");
treeMap.put("third", "Banana");
treeMap.put("fourth", "Apple");You've defined the map to hold integer keys and strings as values, yet you're trying to add string keys and string values to it: that won't work.
If this is a map how do I define if the data should go to the left or to the right of certain node?That is all done for you. In a TreeMap (using the no-args constructor), you can only store objects that are comparable to each other (so, they must implement the Comparable interface!). So the dirty work of deciding if the entry should be stored, or traversed, into the left or right subtree of a node, is all done behind the scenes.
Also note that TreeMap is not backed up by a binary tree, or a binary search tree, but by a red-black tree. A red-black tree is a self balancing binary tree structure.
Should I have dynamical keys so that they increase automatically when adding new data?
According to a webpage I should use Comparator(), is that to find the data in the tree and retrieve the key?
ThanksI am not sure what it is you want. I am under the impression that you have to write a binary tree (or a binary search tree) for a course for school/university. Is that correct? If so, then I don't think you're permitted to use a TreeMap, but you'll have to write your own classes.

Implementation of LISP trees in Java

I have a problem with implementation of a something similar to a LISP tree in Java. That means that I want to be able to combine different if-else-conditions from a set of variables and operators and run it. For example, if (variable) (operator) (variable) (operator2) (variable) (operator) (variable)
whereby :
variable: means a variable
operator: <, >, =, +, _,
variable: variable
operator2: &&, ||, etc
I don't know how to do in a way that a variable can be picked up from a set, operator can be picked up from a set and operator2 can also be picked up from a set.

Lisp doesn't use trees... it uses lists. In fact, Lisp stands for "List Processing".
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How can I link to pages in a 2 level popup index/selection tree with java script?

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1
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break
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break
case "PHRASES FOR LEARNING":
this.pageNum = 56
break
case "DIRECTIONS & TRANSPORTATION":
this.pageNum = 59
break
case "DESCRIBING THE TRAIL":
this.pageNum = 63
break
case "DO'S & DON'TS":
this.pageNum = 68
break
case "EQUIPMENT":
this.pageNum = 74
break
case "FOOD":
this.pageNum = 83
break
case "INTRODUCING A VILLAGE":
this.pageNum = 96
break
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this.pageNum = 105
break
case "HANDICRAFTS":
this.pageNum = 120
break
case "TEMPLES & MONKS":
this.pageNum = 126
break
case "AGRICULTURE":
this.pageNum = 131
break
case "ANIMAL HUSBANDRY":
this.pageNum = 140
break
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this.pageNum = 145
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this.pageNum = 151
break
case "NATIONAL PROTECTED AREAS":
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break
case "IDENTIFYING WILDLIFE":
this.pageNum = 161
break
case "PLANTS & FORESTS":
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case "BOATS":
this.pageNum = 175
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case "HEALTH AND SAFETY":
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2
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Thanks.

Thanks. I've got it now. I was mistakenly renaming itemIndex to each section...Introduction, Alphabet

LOGICAL TREES in JAVA

hi everyone.
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may i ask a few minutes from your time to enlighten me regarding this problem.
please tell me the structure to use, and an example how to use it.
please help.(deadline's in a few days.)
thank you.

Here's a simple Node class - to use them as a tree, all you need is a reference any node, usually the root node.
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+ Root
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          System.err.println(node);
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               print(node.getChildAt(i), indent +"   ");

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Help AVL Tree in JAVA code (remove) question-answer

Hi,
everyone. I have question.
I want codes in Java for AVL Tree.
I but must have remove methods or choose elements.
It`s main for me.
If you know, please write in code JAVA or contact e-mail.
or link to page or if you have self code.
thanks,
regards
[email protected]

I have a better idea.
Why don't you try to do it yourself, and when you get stuck, post your code and details of what difficulty you're having.
When you post code, please use[code] and [/code] tags as described in Formatting tips on the message entry page. It makes it much easier to read.

Tree traversal Java Program

Hi,
I need the below implementation in JAVA :
Scenario : Need to traverse once through all nodes of a tree
Input :
(i) Starting node of traversal
(ii) List of nodes in the Tree
(iii) Parent of all nodes, say, mapping like (each_node, list_of_its_parent) (OR) (each_node, list_of_its_child)
Eg TREE :
A___________________ F
| | | |
|__B | | |
| C D_____|
| |___
H | |
E G
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=============
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That is not a tree;Does it matter? You can always traverse a DAG as a
tree can't you? The A in DAG means acyclic so a DAG
is always also a tree.Check the definitions before you reply please: a DAG
is not "aways also" a tree; no discussion about it. Don't confuse
matters.Who's confusing matters? You introduced the DAG so
you explain why and what consequences it has!No, I just gave a name to what the OP said: s/he didn't show a tree,
s/he showed a DAG; that's all I did.
So a DAG can not always be expanded to a tree? Is that what you're
saying?There's no 'expanding' here; A tree is a very restricted DAG instead.
kind regards,
JosAnd zip up please. Your fake intimacy isn't always wellcome.Stay out of this discussion then; easy as that: a) you lack the knowledge
to participate in this discussion and b) you don't like my friendly greetings,
so the best thing for you, and for this discussion, is that you stay out of it.
kind regards,
Jos

Binary search tree in java using a 2-d array

Good day, i have been wrestling with this here question.
i think it does not get any harder than this. What i have done so far is shown at the bottom.
We want to use both Binary Search Tree and Single Linked lists data structures to store a text. Chaining
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tree contains four fields :
(i) Word
(ii) A pointer pointing to all the lines word appears in
(iii) A pointer pointing to the subtree(left) containing all the words that appears in the text and are
predecessors of word in lexicographic order.
(iv) A pointer pointing to the subtree(right) containing all the words that appears in the text and are
successors of word in lexicographic order.
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String TextID; // Text Identification
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void CreateBinSrchTree (TEXT text){...}
void LinesWordInBinSrchTree(BinSrchTreeWordNode Node){...}
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TEXT univ = new TEXT(6,4);
univ.textcont[0][0] = "Ukzn"; univ.textcont[0][1] ="Uct";
univ.textcont[0][2] ="Wits";univ.textcont[0][3] ="Rhodes";
univ.textcont[1][0] = "stellenbosch";
univ.textcont[1][1] ="FreeState";
univ.textcont[1][2] ="Johannesburg";
univ.textcont[1][3] = "Pretoria" ;
univ.textcont[2][0] ="Zululand";univ.textcont[2][1] ="NorthWest";
univ.textcont[2][2] ="Limpopo";univ.textcont[2][3] ="Wsu";
univ.textcont[3][0] ="NorthWest";univ.textcont[3][1] ="Limpopo";
univ.textcont[3][2] ="Uct";univ.textcont[3][3] ="Ukzn";
univ.textcont[4][0] ="Mit";univ.textcont[4][1] ="Havard";
univ.textcont[4][2] ="Michigan";univ.textcont[4][3] ="Juissieu";
univ.textcont[5][0] ="Cut";univ.textcont[5][1] ="Nmmu";
univ.textcont[5][2] ="ManTech";univ.textcont[5][3] ="Oxford";
// create a binary search tree (universities)
// and insert words of text univ in it
TreeText universities = new TreeText("Universities");
universities.CreateBinSrchTree(univ);
// List words Universities trees with their lines of appearance
System.out.println();
System.out.println(universities.TextID);
System.out.println();
universities.LinesWordInBinSrchTree(universities.RootText);
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BinSrchTreeWordNode LeftTree = null; // precedent words
String word;
LineNode NextLineNode = null; // next line in
// which word appears
BinSrchTreeWordNode RightTree = null; // following words
BinSrchTreeWordNode(String WordValue)
{word = WordValue;} // creates a new node
BinSrchTreeWordNode InsertionBinSrchTree
(String w, int line, BinSrchTreeWordNode bst)
public class LineNode{
int Line; // line in which the word appears
LineNode next = null;
public class TEXT{
int NBRLINES ; // number of lines
int NBRCOLS; // number of columns
String [][] textcont; // text content
TEXT(int nl, int nc){textcont = new String[nl][nc];}
The method InsertionBinSrchTree inserts a word (w) in the Binary search tree. The method Create-
BinSrchTree creates a binary search tree by repeated calls to InsertionBinSrchTree to insert elements
of text. The method LinesWordInBinSrchTree traverses the Binary search tree inorder and displays the
words with the lines in which each appears.
>>>>>>>>>>>>>>>>>>>>>>
//InsertionBinTree is of type BinSearchTreeWordNode
BinSrchTreeWordNode InsertionBinSrchTree(String w, int line,                                             BinSrchTreeWordNode bst)
//First a check must be made to make sure that we are not trying to //insert a word into an empty tree. If tree is empty we just create a //new node.
     If (bst == NULL)
               System.out.println(Tree was empty)
     For (int rows =0; rows <= 6; rows++)
               For (int cols = 0; cols <= 4; cols++)
                    Textcont[i][j] = w

What is the purpose of this thread? You are yet to ask a question... Such a waste of time...
For future reference use CODE TAGS when posting code in a thread.
But again have a think about how to convey a question to others instead of blabbering on about nothing.
i think it does not get any harder than this.What is so difficult to understand. Google an implementation of a binary tree using a single array. Then you can integrate this into the required 2-dimension array for your linked list implemented as an array in your 2-d array.
Mel

Implementation of a parse tree in java (HELP!!!)

I want to be able to do this in java, please how can i implement this.
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          a *
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It's not entirely clear what you want to do. That expression in infix notation (standard notation) would be "(b a c) + *" which doesn't make any sense. The leaves of the tree should be values, and non-leaf nodes should be operators. You can implement this by using a tree datatype in Java.

Implementation of a parse tree in Java (Urgent)

How best can a parse tree be implemented in java, i have read some online information that suggest use of data structures, but i am still not clear on how to do it.

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