LeetCode Inorder Successor in BST

原题链接在这里：https://leetcode.com/problems/inorder-successor-in-bst/

题目：

Given a binary search tree and a node in it, find the in-order successor of that node in the BST.

Note: If the given node has no in-order successor in the tree, return null.

题解：

successor could be自己的parent, or 右子树中最左的点.

For both cases, if p.val < root.val, update successor as root. Otherwise, root needs to be bigger, root = root.right.

Time Complexity: O(h).

Space: O(1).

AC Java:

 /**

  * Definition for a binary tree node.

  * public class TreeNode {

  *     int val;

  *     TreeNode left;

  *     TreeNode right;

  *     TreeNode(int x) { val = x; }

  * }

  */

 public class Solution {

     public TreeNode inorderSuccessor(TreeNode root, TreeNode p) {

         if(root == null || p == null){

             return null;

         }

         TreeNode successor = null;

         while(root != null){

             if(p.val < root.val){

                 successor = root;

                 root = root.left;

             }else{

                 root = root.right;

             }

         }

         return successor;

     }

 }

跟上Inorder Successor in BST II.

巴特西

LeetCode Inorder Successor in BST

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