sarahzhao25

checkAndRotateRoots(root) {
  if (root) {
    let x = root.balanceFactor();
    if (x > 1 || x < -1) rotate(root);
    checkAndRotateRoots(root.parent.node);
  }
}

sarahzhao25

BinarySearchTree.prototype.height = function(treeNode) {
  return (treeNode === null) ? -1 : Math.max(this.height(treeNode.left), this.height(treeNode.right)) + 1;
};