tree.java

这是一个遍历树的深度的小程序

// Fig. 20.17: Tree.java
// Definition of class TreeNode and class Tree.
package com.deitel.jhtp5.ch20;

// class TreeNode definition
class TreeNode {

	// package access members
	TreeNode leftNode;

	int data, depth;

	TreeNode rightNode;

	// initialize data and make this a leaf node
	public TreeNode(int nodeData) {
		data = nodeData;
		leftNode = rightNode = null; // node has no children
	}

	public TreeNode(int nodeData, int dep) {
		data = nodeData;
		leftNode = rightNode = null; // node has no children
		depth = dep;
	}

	// locate insertion point and insert new node; ignore duplicate values
	public synchronized void insert(int insertValue) {
		// insert in left subtree
		if (insertValue < data) {

			// insert new TreeNode
			if (leftNode == null)
				leftNode = new TreeNode(insertValue);

			else
				// continue traversing left subtree
				leftNode.insert(insertValue);
		}

		// insert in right subtree
		else if (insertValue > data) {

			// insert new TreeNode
			if (rightNode == null)
				rightNode = new TreeNode(insertValue);

			else
				// continue traversing right subtree
				rightNode.insert(insertValue);
		}

	} // end method insert

} // end class TreeNode

// class Tree definition
public class Tree {

	private TreeNode root;

	// construct an empty Tree of integers
	public Tree() {
		root = null;
	}

	// insert a new node in the binary search tree
	public synchronized void insertNode(int insertValue) {
		if (root == null)
			root = new TreeNode(insertValue); // create the root node here

		else {
			// root.depth =
			// Math.max(root.leftNode.depth,root.rightNode.depth)-1;
			root.insert(insertValue); // call the insert method
		}
	}

	// test the Depth
	public synchronized void getDepth() {
		System.out.println("\n"+getDepthHelper(root));
	}

	// Depth test Helper
	public int getDepthHelper(TreeNode node) {
		int depth = 0;
		int temp1 = 0;
		int temp2 = 0;

		if (node == null) {
			return 0;
		} else {
			temp1 = getDepthHelper(node.leftNode);
			temp2 = getDepthHelper(node.rightNode);
			depth = (temp1 > temp2 ? temp1 : temp2);
			depth++;
			return depth;
		}
	}

	// begin preorder traversal
	public synchronized void preorderTraversal() {
		preorderHelper(root);
	}

	// 前序
	// recursive method to perform preorder traversal
	private void preorderHelper(TreeNode node) {
		if (node == null)
			return;

		System.out.print(node.data + " "); // output node data
		preorderHelper(node.leftNode); // traverse left subtree
		preorderHelper(node.rightNode); // traverse right subtree
	}

	// begin inorder traversal
	public synchronized void inorderTraversal() {
		inorderHelper(root);
	}

	// 中序
	// recursive method to perform inorder traversal
	private void inorderHelper(TreeNode node) {
		if (node == null)
			return;

		inorderHelper(node.leftNode); // traverse left subtree
		System.out.print(node.data + " "); // output node data
		inorderHelper(node.rightNode); // traverse right subtree
	}

	// begin postorder traversal
	public synchronized void postorderTraversal() {
		postorderHelper(root);
	}

	// 后序
	// recursive method to perform postorder traversal
	private void postorderHelper(TreeNode node) {
		if (node == null)
			return;

		postorderHelper(node.leftNode); // traverse left subtree
		postorderHelper(node.rightNode); // traverse right subtree
		System.out.print(node.data + " "); // output node data
	}

} // end class Tree

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