/** @lc app=leetcode.cn id=94 lang=javascript** [94] 二叉树的中序遍历*/// @lc code=start
/*** Definition for a binary tree node.* function TreeNode(val, left, right) {*     this.val = (val===undefined ? 0 : val)*     this.left = (left===undefined ? null : left)*     this.right = (right===undefined ? null : right)* }*/
/*** @param {TreeNode} root* @return {number[]}*/
var inorderTraversal = function(root) {let ans = [];const inorder = root => {if(root==null) return;inorder(root.left)ans.push(root.val)inorder(root.right)}inorder(root);return ans;
};
// @lc code=end