JavaScript:如何实现二叉搜索树

Question

我正在 JavaScript 中实现二叉搜索树，但是在编写插入函数时，发生了一些错误(很可能在 RECURSION 中)。

这是我的代码:

class BinarySearchTree {
  constructor() {
    this.length = 0;
    this.root = null;
  }
  insert(elem) {
    if (!this.root) {
      //If root is null then this is the root.
      this.root = new BSTNode(elem);
    } else {
      let newNode = new BSTNode(elem);
      let myRoot = this.getParent(this.root, elem)
      console.log(myRoot);

      if (myRoot[1] == 'left') myRoot[0].left = newNode;      //Error Line
      else myRoot[0].right = newNode;

      this.nodes.push(newNode);
      this.arr.push(elem);
    }
    this.length++
  }
  getParent(root, elem) { // the argument 'root' is ambiguous, but it is for the user

    if (elem < root.value) {
      if (root.left!==null) this.getParent(root.left, elem); 
      else return [root, 'left'];
    } else {
      if (root.right!==null) this.getParent(root.right, elem);
      else return [root, 'right']
    }
  }
}
class BSTNode {
  constructor(val) {
    this.value = val;
    this.left = null; //Left Node
    this.right = null; //Right Node
  }
}

有两个类；即 BinarySearchTree和 BSTNode .

错误: Uncaught TypeError: Cannot read property '1' of undefined
我无法找到错误。

请注意，也欢迎使用其他解决方案来做同样的事情。

Answer 1

你应该返回 this.getParent(root.left, elem); 的结果和 this.getParent(root.right, elem);

getParent(root, elem) { // the argument 'root' is ambiguous, but it is for the user

    if (elem < root.value) {

      if (root.left!==null) return this.getParent(root.left, elem); 
      else return [root, 'left'];
    } else {
      if (root.right!==null) return this.getParent(root.right, elem);
      else return [root, 'right']
    }
  }