Update 37. 序列化二叉树.md

题目链接改为力扣中的对应题目，题目描述和代码按该题的接口调整。

notes/37. 序列化二叉树.md

@@ -1,6 +1,6 @@
 # 37. 序列化二叉树
 
-[NowCoder](https://www.nowcoder.com/practice/cf7e25aa97c04cc1a68c8f040e71fb84?tpId=13&tqId=11214&tPage=1&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking&from=cyc_github)
+[Leetcode](https://leetcode.cn/problems/xu-lie-hua-er-cha-shu-lcof/)
 
 ## 题目描述
 
@@ -9,31 +9,39 @@
 ## 解题思路
 
 ```java
-private String deserializeStr;
+class Codec {
 
-public String Serialize(TreeNode root) {
-    if (root == null)
-        return "#";
-    return root.val + " " + Serialize(root.left) + " " + Serialize(root.right);
-}
+    private String deserializeStr;
 
-public TreeNode Deserialize(String str) {
-    deserializeStr = str;
-    return Deserialize();
-}
+    // Encodes a tree to a single string.
+    public String serialize(TreeNode root) {
+        if (root == null) {
+            return "#";
+        }
+        return root.val + " " + serialize(root.left) + " " + serialize(root.right);
+    }
 
-private TreeNode Deserialize() {
-    if (deserializeStr.length() == 0)
-        return null;
-    int index = deserializeStr.indexOf(" ");
-    String node = index == -1 ? deserializeStr : deserializeStr.substring(0, index);
-    deserializeStr = index == -1 ? "" : deserializeStr.substring(index + 1);
-    if (node.equals("#"))
-        return null;
-    int val = Integer.valueOf(node);
-    TreeNode t = new TreeNode(val);
-    t.left = Deserialize();
-    t.right = Deserialize();
-    return t;
+    // Decodes your encoded data to tree.
+    public TreeNode deserialize(String data) {
+        deserializeStr = data;
+        return deserialize();
+    }
+
+    private TreeNode deserialize() {
+        if (deserializeStr.length() == 0) {
+            return null;
+        }
+        int index = deserializeStr.indexOf(" ");
+        String node = index == -1 ? deserializeStr : deserializeStr.substring(0, index);
+        deserializeStr = index == -1 ? "" : deserializeStr.substring(index + 1);
+        if (node.equals("#")) {
+            return null;
+        }
+        int val = Integer.parseInt(node);
+        TreeNode t = new TreeNode(val);
+        t.left = deserialize();
+        t.right = deserialize();
+        return t;
+    }
 }
 ```