Published Jun 25, 2022
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Given the root of a binary search tree, and an integer k, return the kth smallest value (1-indexed) of all the values of the nodes in the tree.
Input: root = [3,1,4,null,2], k = 1
Output: 1
Input: root = [5,3,6,2,4,null,null,1], k = 3
Output: 3
n.1 <= k <= n <= 10^40 <= Node.val <= 10^4/**
* Definition for a binary tree node.
* class TreeNode {
* val: number
* left: TreeNode | null
* right: TreeNode | null
* constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.left = (left===undefined ? null : left)
* this.right = (right===undefined ? null : right)
* }
* }
*/
function kthSmallest(root: TreeNode | null, k: number): number {
let res;
const travel = (node: TreeNode) => {
if(node === null) return
if(k === 0) return
travel(node.left)
k--;
if(k === 0) res = node.val;
travel(node.right)
}
travel(root)
return res
};