|  |  |  | @ -638,3 +638,19 @@ class Solution { | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ``` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### [68 - II. 二叉树的最近公共祖先](https://leetcode-cn.com/problems/er-cha-shu-de-zui-jin-gong-gong-zu-xian-lcof/) | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ```java | 
			
		
	
		
			
				
					|  |  |  |  | class Solution { | 
			
		
	
		
			
				
					|  |  |  |  |     public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { | 
			
		
	
		
			
				
					|  |  |  |  |         if(root == null || root == p || root == q) return root; | 
			
		
	
		
			
				
					|  |  |  |  |         TreeNode left = lowestCommonAncestor(root.left, p, q); | 
			
		
	
		
			
				
					|  |  |  |  |         TreeNode right = lowestCommonAncestor(root.right, p, q); | 
			
		
	
		
			
				
					|  |  |  |  |         if(left == null && right == null) return null; // 1. | 
			
		
	
		
			
				
					|  |  |  |  |         if(left == null) return right; // 3. | 
			
		
	
		
			
				
					|  |  |  |  |         if(right == null) return left; // 4. | 
			
		
	
		
			
				
					|  |  |  |  |         return root; // 2. if(left != null and right != null) | 
			
		
	
		
			
				
					|  |  |  |  |     } | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ``` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
	
		
			
				
					|  |  |  | 
 |