JavaScript实现简单的二叉树中序遍历(class / prototype 写法)(附 Python)

本文介绍如何使用JavaScript和Python构建二叉树结构，并实现中序遍历算法。通过实例演示了二叉树节点的创建、连接及遍历过程，展示了不同编程语言下二叉树的构建和遍历实现。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

二叉树

一棵简单的二叉树如图。

构建二叉树

首先，构建如图的二叉树，并添加一个打印该树的方法 printTheTree。

ES6 class 语法如下

class TreeNode {
  constructor(value) {
    this.value = value
    this.left = null
    this.right = null
  }

  printTheTree() {
    console.log(`root value is ${this.value}, left child is ${JSON.stringify(this.left)}, right child is ${JSON.stringify(this.right)}`)
  }
}

const node3 = new TreeNode(3)
const node1 = new TreeNode(1)
const node6 = new TreeNode(6)
const node4 = new TreeNode(4)
const node7 = new TreeNode(7)

node3.left = node1
node3.right = node6
node6.left = node4
node6.right = node7

node3.printTheTree()

不用语法糖，直接用原型链描述如下

var TreeNode = function (value) {
  this.value = value
  this.left = null
  this.right = null
}

TreeNode.prototype.printTheTree = function () {
  console.log(`root value is ${this.value}, left child is ${JSON.stringify(this.left)}, right child is ${JSON.stringify(this.right)}`)
}

const node3 = new TreeNode(3)
const node1 = new TreeNode(1)
const node6 = new TreeNode(6)
const node4 = new TreeNode(4)
const node7 = new TreeNode(7)

node3.left = node1
node3.right = node6
node6.left = node4
node6.right = node7

node3.printTheTree()

打印得到 root value is 3, left child is {“value”:1,“left”:null,“right”:null}, right child is {“value”:6,“left”:{“value”:4,“left”:null,“right”:null},“right”:{“value”:7,“left”:null,“right”:null}}

中序遍历

中序遍历的顺序是 “左根右”，用递归实现如下

const inorderTraversal = (node) => {
  if (!node) return
  inorderTraversal(node.left)
  console.log(node.value)
  inorderTraversal(node.right)
}

打印得到 1 3 4 6 7

Python 描述

class TreeNode:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None
    def __str__(self):
        return "{left child is %s, root value is  %s, right child is %s}" % (self.left, self.value, self.right)

def myPrint(node):
    if node is None:
        return
    myPrint(node.left)
    print node.value,
    myPrint(node.right)

node3 = TreeNode(3)
node1 = TreeNode(1)
node6 = TreeNode(6)
node4 = TreeNode(4)
node7 = TreeNode(7)

node3.left = node1
node3.right = node6
node6.left = node4
node6.right = node7


print node3
myPrint(node3)