首发于 语雀文档@blueju

    代码：

    1. /**
    2.  * Definition for a binary tree node.
    3.  * class TreeNode {
    4.  *     val: number
    5.  *     left: TreeNode | null
    6.  *     right: TreeNode | null
    7.  *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
    8.  *         this.val = (val===undefined ? 0 : val)
    9.  *         this.left = (left===undefined ? null : left)
    10.  *         this.right = (right===undefined ? null : right)
    11.  *     }
    12.  * }
    13.  */
    15. function kthLargest(root, k) {
    16.     const treeNodeList = []
    17.     const check = (root) => {
    18.         if (root === null)
    19.             return
    20.         treeNodeList.push(root.val)
    21.         check(root.left)
    22.         check(root.right)
    23.     }
    24.     check(root)
    25.     const afterSort = treeNodeList.sort((a, b) => b - a)
    26.     return afterSort[k - 1]
    27. };