Merge pull request #101 from Joshua-Lu/patch-18

更新 0236.二叉树的最近公共祖先 Java版本

problems/0236.二叉树的最近公共祖先.md

@@ -223,7 +223,32 @@ public:
 
 
 Java：
+
+```Java
+class Solution {
+    public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
+        return lowestCommonAncestor1(root, p, q);
+
+    }
+    public TreeNode lowestCommonAncestor1(TreeNode root, TreeNode p, TreeNode q) {
+        if (root == null || root == p || root == q) {
+            return root;
+        }
+        TreeNode left = lowestCommonAncestor1(root.left, p, q);
+        TreeNode right = lowestCommonAncestor1(root.right, p, q);
+        if (left != null && right != null) {// 左右子树分别找到了，说明此时的root就是要求的结果
+            return root;
+        }
+        if (left == null) {
+            return right;
+        }
+        return left;
+    }
+}
+```
+
 ```java
+// 代码精简版
 class Solution {
     TreeNode pre;
     public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
@@ -236,7 +261,6 @@ class Solution {
         else return null;
     }
 }
-```
 
 Python：