链式二叉树的实现(Java)

定义树节点：

package 链式二叉树;

public class TreeNode {

	private Object data;
	private TreeNode left;
	private TreeNode right;

	public TreeNode() {
		this.data = null;
		this.left = null;
		this.right = null;
	}

	public TreeNode(Object data, TreeNode left, TreeNode right) {
		this.data = data;
		this.left = left;
		this.right = right;
	}

	public Object getData() {
		return this.data;
	}
	public void setData(Object data) {
		this.data = data;
	}

	public TreeNode getLeft() {
		return this.left;
	}

	public void setLeft(TreeNode left) {
		this.left = left;
	}
	public TreeNode getRight() {
		return this.right;
	}
	public void setRight(TreeNode right) {
		this.right = right;
	}

}

二叉树实现：

package 链式二叉树;

public class BinaryTree {

	public TreeNode root;

	public BinaryTree(TreeNode root) {
		this.root = root;
	}

	public BinaryTree() {
		this.root = null;
	}

	public TreeNode getRoot() {
		return this.root;
	}

	public void setRoot(TreeNode root) {
		this.root = root;
	}

	//前序遍历
	public void preorder(TreeNode root) {
		if(root != null) {
			System.out.println(root.getData());
			preorder(root.getLeft());
			preorder(root.getRight());
		}
	}

	//中序遍历
	public void middleorder(TreeNode root) {
		if(root != null) {
			middleorder(root.getLeft());
			System.out.println(root.getData());
			middleorder(root.getRight());
		}
	}

	//后序遍历
	public void postorder(TreeNode root) {
		if(root != null) {
			postorder(root.getLeft());
			postorder(root.getRight());
			System.out.println(root.getData());
		}
	}

	//获得父节点
	public TreeNode getParent(TreeNode ele) {
		return (root == null || ele == ele) ? null : parent(root, ele);
	}
	private TreeNode parent(TreeNode root, TreeNode e) {
		if(root == null) return null;
		if(root.getLeft() == e || root.getRight() == e) return root;
		TreeNode t;
		return ((t = parent(root.getLeft(), e)) != null) ? t : parent(root.getRight(), e);
	}

	//获得节点个数
	public int getSize() {
		return length(root);
	}
	private int length(TreeNode root) {
		return root == null ? 0 : (length(root.getLeft()) + length(root.getRight()) + 1);
	}

	//获得树的深度
	public int getDepth() {
		return depth(root);
	}
	private int depth(TreeNode root) {
		if(root == null) return 0;
		int m = depth(root.getLeft());
		int n = depth(root.getRight());
		return m > n ? m+1 : n+1;
	}

	public static void main(String[] args) {
		         TreeNode l12 = new TreeNode("left12", null, null);
		         TreeNode r12 = new TreeNode("right12", null, null);
		         TreeNode l22 = new TreeNode("left22", null, null);
		         TreeNode r22 = new TreeNode("right22", null, null);

		         TreeNode l1 = new TreeNode("left1", l12, r12);// 根节点左子树
		         TreeNode r1 = new TreeNode("right1", l22, r22);// 根节点右子树
		         TreeNode root = new TreeNode("root", l1, r1);// 创建根节点

		         BinaryTree bt = new BinaryTree(root);
//		         System.out.println("=======先序遍历======");
//		         bt.preorder(bt.getRoot());
//		         System.out.println("=======中序遍历======");
//		         bt.middleorder(bt.getRoot());
		         System.out.println("深度:"+ bt.getDepth());
	}
}