# Question

Formatted question description: https://leetcode.ca/all/235.html

 235. Lowest Common Ancestor of a Binary Search Tree

Given a binary search tree (BST),
find the lowest common ancestor (LCA) of two given nodes in the BST.

According to the definition of LCA on Wikipedia:
“The lowest common ancestor is defined between two nodes p and q
as the lowest node in T that has both p and q as descendants
(where we allow a node to be a descendant of itself).”

Given binary search tree:  root = [6,2,8,0,4,7,9,null,null,3,5]

_______6______
/              \
___2__          ___8__
/      \        /      \
0      _4       7       9
/  \
3   5

Example 1:

Input: root = [6,2,8,0,4,7,9,null,null,3,5], p = 2, q = 8
Output: 6
Explanation: The LCA of nodes 2 and 8 is 6.

Example 2:

Input: root = [6,2,8,0,4,7,9,null,null,3,5], p = 2, q = 4
Output: 2
Explanation: The LCA of nodes 2 and 4 is 2, since a node can be a descendant of itself
according to the LCA definition.

Note:

All of the nodes' values will be unique.
p and q are different and both values will exist in the BST.

@tag-tree


# Algorithm

If the value of the root node is greater than the larger value between p and q, indicating that both p and q are in the left subtree, then we enter the left child node of the root node to continue recursion,

If the root node is less than the smaller value between p and q, indicating that both p and q are in the right subtree, then we enter the right child node of the root node to continue recursion,

If neither, it means that the current root node is the smallest common parent node and return directly.

Java