标签：root tree void private always treenode ini arc elements
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.
Note:
You may assume k is always valid, 1 ≤ k ≤ BST‘s total elements.
Example 1:
Input: root = [3,1,4,null,2], k = 1 3 / 1 4 2 Output: 1
Example 2:
Input: root = [5,3,6,2,4,null,null,1], k = 3
5
/ 3 6
/ 2 4
/
1
Output: 3
1 /** 2 * Definition for a binary tree node. 3 * public class TreeNode { 4 * int val; 5 * TreeNode left; 6 * TreeNode right; 7 * TreeNode(int x) { val = x; } 8 * } 9 */ 10 class Solution { 11 int res; 12 int count; 13 public int kthSmallest(TreeNode root, int k) { 14 res = 0; 15 count = k; 16 inOrder(root); 17 return res; 18 } 19 20 private void inOrder(TreeNode root) { 21 if (root == null) { 22 return; 23 } 24 inOrder(root.left); 25 count -= 1; 26 if (count == 0) { 27 res = root.val; 28 return; 29 } 30 inOrder(root.right); 31 } 32 }
[LC] 230. Kth Smallest Element in a BST
标签：root tree void private always treenode ini arc elements
原文地址：https://www.cnblogs.com/xuanlu/p/12000770.html
