Merge pull request #2729 from eliozh/master

Update 0236.二叉树的最近公共祖先.md

Author: youngyangyang04

problems/0236.二叉树的最近公共祖先.md

@@ -454,7 +454,11 @@ impl Solution {
         p: Option<Rc<RefCell<TreeNode>>>,
         q: Option<Rc<RefCell<TreeNode>>>,
     ) -> Option<Rc<RefCell<TreeNode>>> {
-        if root == p || root == q || root.is_none() {
+        if root.is_none() {
+            return root;
+        }
+        if Rc::ptr_eq(root.as_ref().unwrap(), p.as_ref().unwrap()) 
+            || Rc::ptr_eq(root.as_ref().unwrap(), q.as_ref().unwrap()) {
             return root;
         }
         let left = Self::lowest_common_ancestor(