public class SearchTree {
    private TreeNode root;

    public TreeNode getRoot() {
        return root;
    }

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

    public SearchTree(){

    }

    /**
     *
     * 创建查找二叉树，添加结点
     */
    public TreeNode put(int data){
        TreeNode node = null;
        TreeNode parent = null;
        if(root == null){
            node = new TreeNode(0,data);
            root = node;
            return node;
        }
        node = root;
        while(node != null){
            parent = node;
            if(data > node.data){
                node = node.rightTreeNode;
            }else if (data < node.data){
                node = node.leftTreeNode;
            }else {
                return node;
            }
        }
        node = new TreeNode(0,data);
        if(data < parent.data){
            parent.leftTreeNode = node;
        }else{
            parent.rightTreeNode = node;
        }
        node.parent = parent;
        return node;
    }

    private void deleteNode(int key) throws Exception{
        TreeNode node = searchNode(key);
        if(node == null)
            throw new Exception("该结点无法找到");
        else
            delete(node);

    }

    private TreeNode searchNode(int key){
        TreeNode node = root;
        if(node == null) {
            return null;
        }else{
            while(node != null && key != node.data){
                    if(key < node.data){
                        node = node.leftTreeNode;
                    }else{
                        node = node.rightTreeNode;
                    }
            }
        }
            return node;
    }
    private void delete(TreeNode node) throws Exception {
        if (node == null){
            throw new Exception("该结点为空，无法找到");
        }else{
            TreeNode parent = node.parent;
            //被删除的结点无左右孩子
            if(node.leftTreeNode == null && node.rightTreeNode == null){
                if(parent.leftTreeNode == node)
                    parent.leftTreeNode = null;
                else
                    parent.rightTreeNode = null;

                return;
            }
            //被删除结点有左无右
            if(node.leftTreeNode != null && node.rightTreeNode == null){
                if(parent.leftTreeNode == node){
                    parent.leftTreeNode = node.leftTreeNode;
                }else if (parent.rightTreeNode == node){
                    parent.rightTreeNode = node.leftTreeNode;
                }

                return;
            }

            //被删除结点有右无左
            if(node.leftTreeNode == null && node.rightTreeNode != null){
                if(parent.leftTreeNode == node){
                    parent.leftTreeNode = node.rightTreeNode;
                }else if(parent.rightTreeNode == node){
                    parent.rightTreeNode = node.rightTreeNode;
                }
                return ;
            }
            //被删除的结点既有左孩子又有右孩子
            TreeNode next = getNextNode(node);
            node.data = next.data;
            delete(next);
        }
    }

    //查找一个结点的后继结点
    private TreeNode getNextNode(TreeNode node){
            if(node == null){
                return null;
            }
            if(node.rightTreeNode != null) {
                //找某结点最小关键字结点
               return getMinTreeNode(node.rightTreeNode);
            }else{
                TreeNode parent = node.parent;
                while(parent != null && node == parent.rightTreeNode){
                    node = parent;
                    parent = parent.parent;
                }
                return parent;
            }

    }


    private TreeNode getMinTreeNode(TreeNode node){
        if(node == null)
            return null;
        while(node.leftTreeNode != null){
            node = node.leftTreeNode;
        }
        return node;
    }

    class TreeNode{
        private int index;
        private TreeNode leftTreeNode;
        private TreeNode rightTreeNode;
        private TreeNode parent;
        private int data;

        public TreeNode(int index,int data){
            this.data = data;
            this.index = index;
            this.leftTreeNode = null;
            this.rightTreeNode = null;
            this.parent = null;
        }

        public int getIndex() {
            return index;
        }

        public void setIndex(int index) {
            this.index = index;
        }

        public TreeNode getLeftTreeNode() {
            return leftTreeNode;
        }

        public void setLeftTreeNode(TreeNode leftTreeNode) {
            this.leftTreeNode = leftTreeNode;
        }

        public TreeNode getRightTreeNode() {
            return rightTreeNode;
        }

        public void setRightTreeNode(TreeNode rightTreeNode) {
            this.rightTreeNode = rightTreeNode;
        }

        public TreeNode getParent() {
            return parent;
        }

        public void setParent(TreeNode parent) {
            this.parent = parent;
        }

        public int getData() {
            return data;
        }

        public void setData(int data) {
            this.data = data;
        }
    }
}