feature: add go solution for leetcode 0235

Author: hzliangbin

solution/0200-0299/0235.Lowest Common Ancestor of a Binary Search Tree/README.md

@@ -100,9 +100,37 @@ class Solution {
 }
 ```
 
-### **...**
-```
+### **Go**
+
+```go
+/**
+ * Definition for TreeNode.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *ListNode
+ *     Right *ListNode
+ * }
+ */
+ func lowestCommonAncestor(root, p, q *TreeNode) *TreeNode {
+    if root == nil {
+        return nil
+    }
 
+    for root != nil {
+        //如果p、q的值都小于root，说明p q 肯定在root的左子树中；
+        //如果p q都大于root，说明肯定在root的右子树中
+        //如果一个在左一个在右 则说明此时的root记为对应的最近公共祖先
+        if root.Val > p.Val && root.Val > q.Val {
+            root = root.Left
+        } else if root.Val < p.Val && root.Val < q.Val {
+            root = root.Right
+        } else {
+            return root
+        }
+    }
+    return nil
+}
 ```
 
-<!-- tabs:end -->
+<!-- tabs:end -->
+

solution/0200-0299/0235.Lowest Common Ancestor of a Binary Search Tree/Solution.go

@@ -0,0 +1,27 @@
+/**
+ * Definition for TreeNode.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *ListNode
+ *     Right *ListNode
+ * }
+ */
+ func lowestCommonAncestor(root, p, q *TreeNode) *TreeNode {
+    if root == nil {
+        return nil
+    }
+
+    for root != nil {
+        //如果p、q的值都小于root，说明p q 肯定在root的左子树中；
+        //如果p q都大于root，说明肯定在root的右子树中
+        //如果一个在左一个在右 则说明此时的root记为对应的最近公共祖先
+        if root.Val > p.Val && root.Val > q.Val {
+            root = root.Left
+        } else if root.Val < p.Val && root.Val < q.Val {
+            root = root.Right
+        } else {
+            return root
+        }
+    }
+    return nil
+}