[javaSE] 数据结构（二叉查找树-插入节点）

public class BSTree<T extends Comparable<T>> {
    private BSTNode<T> mRoot;

    /**
     * 定义二叉树
     * 
     * @author taoshihan
     * @param <T>
     * 
     */
    public class BSTNode<T extends Comparable<T>> {
        public T key;
        public BSTNode parent, left, right;

        public BSTNode(T key, BSTNode parent, BSTNode left, BSTNode right) {
            this.key = key;
            this.parent = parent;
            this.left = left;
            this.right = right;
        }
    }

    public void insert(BSTree bsTree, BSTNode bstNode) {
        BSTNode parent = null;
        BSTNode x = bsTree.mRoot;
        // 查找bstNode的插入位置，x的指针指对
        while (x != null) {
            parent = x;// 把x的位置作为节点的父类
            int flag = bstNode.key.compareTo(x.key);
            if (flag < 0) {
                x = x.left;
            }else{
                x=x.right;
            }
        }
        // 插入
        bstNode.parent = parent;
        if(parent==null){
            bsTree.mRoot=bstNode;
        }else{
            int flag = bstNode.key.compareTo(parent.key);
            if (flag < 0) {
                parent.left = bstNode;
            } else {
                parent.right = bstNode;
            }        
        }

    }

    /**
     * 插入根节点
     * 
     * @param key
     */
    public void insert(T key) {
        BSTNode<T> z = new BSTNode<T>(key, null, null, null);
        // 如果新建结点失败，则返回。
        if (z != null)
            insert(this, z);
    }
    /*
     * 打印"二叉查找树"
     *
     * key        -- 节点的键值 
     * direction  --  0，表示该节点是根节点;
     *               -1，表示该节点是它的父结点的左孩子;
     *                1，表示该节点是它的父结点的右孩子。
     */
    private void print(BSTNode<T> tree, T key, int direction) {
        
        if(tree != null) {

            if(direction==0)    // tree是根节点
                System.out.printf("%2d is root\n", tree.key);
            else                // tree是分支节点
                System.out.printf("%2d is %2d‘s %6s child\n", tree.key, key, direction==1?"right" : "left");

            print(tree.left, tree.key, -1);
            print(tree.right,tree.key,  1);
        }
    }

    public void print(BSTree<T> tree) {
        if (tree.mRoot != null){
            print(tree.mRoot, tree.mRoot.key, 0);
        }
    }
    /**
     * @param args
     */
    public static void main(String[] args) {
        BSTree tree = new BSTree();
        tree.insert(3);
        tree.insert(1);
        tree.insert(2);
        tree.insert(5);
        tree.insert(4);
        tree.insert(6);
        tree.print(tree);
    }

}