Package g0201_0300.s0235_lowest_common_ancestor_of_a_binary_search_tree

Class Solution

  • public class Solution
extends Object
    235 - Lowest Common Ancestor of a Binary Search Tree\. Easy 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](https://en.wikipedia.org/wiki/Lowest_common_ancestor): “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** ).” **Example 1:** ![](https://assets.leetcode.com/uploads/2018/12/14/binarysearchtree_improved.png) **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:** ![](https://assets.leetcode.com/uploads/2018/12/14/binarysearchtree_improved.png) **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. **Example 3:** **Input:** root = [2,1], p = 2, q = 1 **Output:** 2 **Constraints:** * The number of nodes in the tree is in the range [2, 105]. * -109 <= Node.val <= 109 * All `Node.val` are **unique**. * `p != q` * `p` and `q` will exist in the BST.