Update 0236.二叉树的最近公共祖先.md

添加 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 +223,28 @@ 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;
+    }
+}
+```
 
 Python：