function Node(data , left,right){
  this.data = data;
  this.left = left;
  this.right = right;
  this.show = show;
  function show(){
    return this.data;
  }
};
function Bst(){
  this.root = null;
  this.insert = insert;//插入
  this.inOrder = inOrder;//中序遍历(升序)
  this.inOrderDesc = inOrderDesc;//中序遍历(降序)
  this.preOrder = preOrder;//先序遍历
  this.postOrder = postOrder;//后续遍历
  this.getMin = getMin;//最大值
  this.getMax = getMax;//最小值
  this.find = find;//查找值
  this.remove = remove;//删除节点
  this.count = count;//获取节点数量
  function insert(data){
    //创建一个新的节点
    var newNode = new Node(data,null,null);
    //判断是否存在根节点，没有将新节点存入
    if(this.root == null){
      this.root = newNode;
    }else{
      //获取根节点
      var current = this.root;
      var parent;
      while(true){
        //将当前节点保存为父节点
        parent = current;
        //将小的数据放在左节点
        if(data < current.data){
          //获取当前节点的左节点
          //判断当前节点下的左节点是否有数据
          current = current.left;
          if(current == null){
            //如果没有数据将新节点存入当前节点下的左节点
            parent.left = newNode;
            break;
          }
        }else{
          current = current.right;
          if(current == null){
            parent.right = newNode;
            break;
          }
        }
      }
    }
  }
  function inOrder(node){
    var data = [];
    _inOrder(node,data);
    return data;
  }
  function inOrderDesc(node){
    var data = [];
    _inOrderDesc(node,data);
    return data;
  }
  function preOrder(node){
    var data = [];
    _preOrder(node,data);
    return data;
  }
  function postOrder(node){
    var data = [];
    _postOrder(node,data);
    return data;
  }
  function _inOrder(node,data){
    if(!(node == null)){
      _inOrder(node.left,data);
      data.push(node.show());
      _inOrder(node.right,data);
    }
  }
  function _inOrderDesc(node,data){
    debugger;
    if(!(node == null)){
      _inOrderDesc(node.right,data);
      data.push(node.show());
      _inOrderDesc(node.left,data);
    }
  }
  function _preOrder(node,data){
    if(!(node == null)){
      data.push(node.show());
      _preOrder(node.left,data);
      _preOrder(node.right,data);
    }
  }
  function _postOrder(node,data){
    if(!(node == null)){
      _postOrder(node.left,data);
      _postOrder(node.right,data);
      data.push(node.show());
    }
  }
  function getMin(){
    var current = this.root;
    while(!(current.left == null)){
    current = current.left;
    }
    return current.data;
  }
  function getMax(){
    var current = this.root;
    while(!(current.right == null)){
    current = current.right;
    }
    return current.data;
  }
  function find(data){
    var current = this.root;
    while(current != null){
      if(data == current.data){
        return current;
      }else if(data < current.data){
        current = current.left;
      }else{
        current = current.right;
      }
    }
    return null;
  }
  function getSmallest(node){
    var current = node;
    while(!(current.left == null)){
      current = current.left;
    }
    return current;
  }
  function remove(data){
    root = removeNode(this.root,data);
  }
  function removeNode(node,data){
    if(node == null){
      return null;
    }
    if(data == node.data){
      //如果没有只节点
      if(node.left == null && node.right){
        return null;
      }
      //如果没有左节点
      if(node.left == null){
        return node.right;
      }
      //如果没有右节点
      if(node.right == null){
        return node.left;
      }
      //有两节点
      var tempNode = getSmallest(node.right);
      node.data = tempNode.data;
      node.right = removeNode(node.right,tempNode.data);
      return node;
    }else if(data < node.data){
      node.left = removeNode(node.left,data);
      return node;
    }else{
      node.right = removeNode(node.right,data);
      return node;
    }
  }
  function count(){
    var counts = 0;
    var current = this.root;
    if(current == null){
      return counts;
    }
    return _count(current,counts);
  }
  function _count(node,counts){
    debugger;
    if(!(node == null)){
      counts ++;
      counts = _count(node.left,counts);;
      counts = _count(node.right,counts);
    }
    return counts;
  }
}