Lowest Common Ancestor of a BST

Given a Binary Search Tree (BST) and two node values p and q, find the lowest common ancestor (LCA) of the two nodes.

The LCA is defined as the lowest node in the tree that has both p and q as descendants (a node is a descendant of itself).

Return the value at the LCA node (not the node itself).

Example

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 (the root), since 2 is in the left subtree and 8 is in the right subtree.

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 4 is in the subtree rooted at 2.

Constraints

• The number of nodes in the tree is in the range [2, 10^5]
• -10^9 <= Node.val <= 10^9
• All node values are unique
• p != q
• p and q will exist in the BST