Merge pull request #1122 from Jerry-306/patch-50

0700 二叉搜索树 部分代码更正

problems/0700.二叉搜索树中的搜索.md

@@ -200,7 +200,7 @@ class Solution {
             if (val < root.val) root = root.left;
             else if (val > root.val) root = root.right;
             else return root;
-        return root;
+        return null;
     }
 }
 ```
@@ -236,7 +236,7 @@ class Solution:
             if val < root.val: root = root.left
             elif val > root.val: root = root.right
             else: return root
-        return root
+        return None
 ```
 
 
@@ -271,7 +271,7 @@ func searchBST(root *TreeNode, val int) *TreeNode {
             break
         }
     }
-    return root
+    return nil
 }
 ```
 
@@ -301,7 +301,6 @@ var searchBST = function (root, val) {
         return searchBST(root.left, val);
     if (root.val < val)
         return searchBST(root.right, val);
-    return null;
 };
 ```
 
@@ -330,7 +329,7 @@ var searchBST = function (root, val) {
         else 
             return root;
     }
-    return root;
+    return null;
 };
 ```