/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
// const diameterOfBinaryTree = function (root) {
//   const value = { height: 0, max: 0 }
//   inorderTraversal(root, value);
//   return value.max;
// };
// const inorderTraversal = function (root, value) {
//   if (root === null) {
//     return 0;
//   }
//   const letfHeight = inorderTraversal(root.right, value);
//   const rightHeight = inorderTraversal(root.left, value);
//   value.max = Math.max(value.max, letfHeight + rightHeight);
//   value.height = (letfHeight > rightHeight ? letfHeight : rightHeight) + 1;
//   return value.height;
// };
const diameterOfBinaryTree = function (root) {
  let value = { max: 0 }
  inorderTraversal(root, value);
  return value.max;
};
const inorderTraversal = function (root, value) {
  if (root === null) {
    return 0;
  }
  const letfHeight = inorderTraversal(root.right, value);
  const rightHeight = inorderTraversal(root.left, value);
  value.max = Math.max(value.max, letfHeight + rightHeight);
  return (letfHeight > rightHeight ? letfHeight : rightHeight) + 1;
};