二叉树的三种遍历方式

  PS： 此算法参考资料《数据结构与算法JavaScript描述》

  1 //------------------------------------------------------------------
//-----------------performance binary tree---------------------
//------------------------------------------------------------------
function Node(data, left, right){
    this.data = data;
    this.left = left;
    this.right = right;
    this.show = show;
}

function show(){
    return this.data;
}

//-----------------------二叉查找树---------------------------------
function BST(){
    this.root = null;
    this.insert = insert;
    this.inOrder = inOrder;
}

//------------------------insert node-------------------------------
function insert(data){
    var node = new Node(data, null, null);
    if(this.root == null){
        this.root = node;
    }else{
        var current = this.root;
        var parent;
        while(true){
            parent = current;
            if(data < current.data){
                current = current.left;
                if(current == null){
                    parent.left = node;
                    break;
                }
            }
            else{
                current = current.right;
                if(current == null){
                    parent.right = node;
                    break;
                }
            }

        }
    }
}

//-------------------中序遍历(升序遍历，从小到大)-------------------
function inOrder(node){
    if(node != null){
        inOrder(node.left);
        console.log(node.show() + ' ');
        inOrder(node.right);
    }
}

//------------------中序遍历测试------------------------------------
var nums = new BST();
nums.insert(23);
nums.insert(45);
nums.insert(16);
nums.insert(37);
nums.insert(3);
nums.insert(22);
nums.insert(99);
console.log('Inorder traversal: ');
inOrder(nums.root);



//------------先序遍历(先根节点，后左节点，右节点)------------------
function preOrder(node){
    if(node != null){
        console.log(node.show());
        preOrder(node.left);
        preOrder(node.right);
    }
}

//------------------先序遍历测试------------------------------------
var nums = new BST();
nums.insert(23);
nums.insert(45);
nums.insert(16);
nums.insert(37);
nums.insert(3);
nums.insert(22);
nums.insert(99);
console.log('preOrder traversal: ');
preOrder(nums.root);


//------------后序遍历(先叶子节点，后左节点，右节点，根节点)--------
function postOrder(node){
    if(node != null){
        postOrder(node.left);
        postOrder(node.right);
        console.log(node.show());
    }
}

//------------------后序遍历测试------------------------------------
var nums = new BST();
nums.insert(23);
nums.insert(45);
nums.insert(16);
nums.insert(37);
nums.insert(3);
nums.insert(22);
nums.insert(99);
console.log('postOrder traversal: ');
postOrder(nums.root);
//------------------------------------------------------------------