คลาส AVL Tree ใน JavaScript

นี่คือการนำ AVL Tree Class ไปใช้งานอย่างสมบูรณ์:

ตัวอย่างโค้ด

class AVLTree {
  constructor() {
    this.root = null;
  }
  getBalanceFactor(root) {
    return this.getHeight(root.left) - this.getHeight(root.right);
  }
  getHeight(root) {
    let height = 0;
    if (root === null || typeof root == "undefined") {
      height = -1;
    } else {
      height = Math.max(this.getHeight(root.left), this.getHeight(root.right)) + 1;
    }
    return height;
  }
  insert(data) {
    let node = new this.Node(data);
    if (this.root === null) {
      this.root = node;
    } else {
      insertHelper(this, this.root, node);
    }
  }
  inOrder() {
    inOrderHelper(this.root);
  }
}
AVLTree.prototype.Node = class {
  constructor(data, left = null, right = null) {
    this.data = data;
    this.left = left;
    this.right = right;
  }
};
function insertHelper(self, root, node) {
  if (root === null) {
    root = node;
  } else if (node.data < root.data) {
    root.left = insertHelper(self, root.left, node);
    if (root.left !== null && self.getBalanceFactor(root) > 1) {
      if (node.data > root.left.data) {
        root = rotationLL(root);
      } else {
        root = rotationLR(root);
      }
    }
  } else if (node.data > root.data) {
    root.right = insertHelper(self, root.right, node);
    if (root.right !== null && self.getBalanceFactor(root) < -1) {
      if (node.data > root.right.data) {
        root = rotationRR(root);
      } else {
        root = rotationRL(root);
      }
    }
  }
  return root;
}
function inOrderHelper(root) {
  if (root !== null) {
    inOrderHelper(root.left);
    console.log(root.data);
    inOrderHelper(root.right);
  }
}
function rotationLL(node) {
  let tmp = node.left;
  node.left = tmp.right;
  tmp.right = node;
  return tmp;
}
function rotationRR(node) {
  let tmp = node.right;
  node.right = tmp.left;
  tmp.left = node;
  return tmp;
}
function rotationLR(node) {
  node.left = rotationRR(node.left);
  return rotationLL(node);
}
function rotationRL(node) {
  node.right = rotationLL(node.right);
  return rotationRR(node);
}