Java implementation of two fork tree construction and 3 kinds of traversal methods

Directory:

1. Assign the value of an array to a binary tree

2. Specific code


1. How to build a tree

Package tree;

Import java.util.LinkedList;
Import java.util.List;

/**
* Function: The value of an array is stored in a two-fork tree and then traversed in 3 ways
*
* Reference 0: Data structure (c language version) Min
*
* Reference 1:http://zhidao.baidu.com/question/81938912.html
*
* Reference 2:http://cslibrary.stanford.edu/110/binarytrees.html#java
*
* @author [email protected] @date: 2011-5-17
*
*/
public class BinTreeTraverse2 {

Private int[] Array = {1, 2, 3, 4, 5, 6, 7, 8, 9};
private static list<node> nodeList = null;

/**
* Inner class: node
*
* @author [email protected] @date: 2011-5-17
*
*/
private Static Class Node {
Node Leftchild;
Node Rightchild;
int data;

Node (int newdata) {
Leftchild = null;
Rightchild = null;
data = NewData;
}
}

public void Createbintree () {
NodeList = new linkedlist<node> ();
Converts the value of an array to node nodes
for (int nodeindex = 0; Nodeindex < array.length; nodeindex++) {
Nodelist.add (the new node (arr Ay[nodeindex]));
}
//To the first LastParentIndex-1 parent node based on the parent node's number relationship with the child node two tree
for (int parentindex = 0; Parentindex < ARRAY.LENGTH/2-1 ; parentindex++) {
//left child
Nodelist.get (parentindex). leftchild = NodeList
. Get (Parentindex * 2 + 1);
Right child
Nodelist.get (parentindex). rightchild = NodeList
. Get (Parentindex * 2 + 2);
}
///Last parent node: Because the last parent node may not have a right child, take it out alone processing
int lastparentindex = ARRAY.LENGTH/2-1;
Left child
Nodelist.get (lastparentindex). leftchild = NodeList
. Get (Lastparentindex * 2 + 1);
Right child, if the length of the array is odd to establish right child
if (array.length% = = 1) {
Nodelist.get (lastparentindex). rightchild = NodeList
. Get ( Lastparentindex * 2 + 2);
}
}

/**
* First Order traversal
*
* These three different traversal structures are the same, but the order is not the same
*
* @param node
* Traversed nodes
*/
public static void Preordertraverse (node node) {
if (node = = null)
Return
System.out.print (Node.data + "");
Preordertraverse (Node.leftchild);
Preordertraverse (Node.rightchild);
}

/**
* Middle Sequence traversal
*
* These three different traversal structures are the same, but the order is not the same
*
* @param node
* Traversed nodes
*/
public static void Inordertraverse (node node) {
if (node = = null)
Return
Inordertraverse (Node.leftchild);
System.out.print (Node.data + "");
Inordertraverse (Node.rightchild);
}

/**
* Post-sequential traversal
*
* These three different traversal structures are the same, but the order is not the same
*
* @param node
* Traversed nodes
*/
public static void Postordertraverse (node node) {
if (node = = null)
Return
Postordertraverse (Node.leftchild);
Postordertraverse (Node.rightchild);
System.out.print (Node.data + "");
}

public static void Main (string[] args) {
BinTreeTraverse2 bintree = new BinTreeTraverse2 ();
Bintree.createbintree ();
The value at the No. 0 index in nodelist is the root node
Node root = nodelist.get (0);

System.out.println ("First Order Traversal:");
Preordertraverse (root);
System.out.println ();

System.out.println ("Middle sequence Traversal:");
Inordertraverse (root);
System.out.println ();

System.out.println ("post-post traversal:");
Postordertraverse (root);
}

}

First-order Traversal:
1 2 4 8 9 5 3 6 7
Middle Sequence Traversal:
8 4 9 2 5 1 6 3 7
Post-post traversal:
8 9 4 5 2 6 7 3 1

Java implementation of two fork tree construction and 3 kinds of traversal methods