text: /*
   * @lc app=leetcode.cn id=230 lang=javascript
   *
   * [230] 二叉搜索树中第K小的元素
   */
  
  // @lc code=start
  /**
   * Definition for a binary tree node.
   * function TreeNode(val) {
   *     this.val = val;
   *     this.left = this.right = null;
   * }
   */
  /**
   * @param {TreeNode} root
   * @param {number} k
   * @return {number}
   */
  var kthSmallest = function(root, k) {
  
  };
  // @lc code=end
  
  //* Testcase Example: '[3,1,4,null,2]\n1'