序列化二叉樹：把二叉樹變成字串
反序列化二叉樹：根據字串建立二叉樹

時間限制：1秒 空間限制：32768K 熱度指數：121974

題目描述
請實現兩個函式，分別用來序列化和反序列化二叉樹

/*
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    private
 
 int index = -1;
    String Serialize(TreeNode root) {
        String str = "";
        if(root == null){
            str += "#,";
            return str;
        }
        str += root.val + ",";
        str += Serialize(root.left);
        str += Serialize(root.right);
        return str;
  }
    TreeNode Deserialize
 
(String str) {
       index++;
       String[] splits = str.split(",");
       TreeNode node = null;
       if(splits[index].equals("#") == false){
           node = new TreeNode(Integer.valueOf(splits[index]));
           node.left = Deserialize(str);
           node.right = Deserialize(str);
       }
 

       return node;
  }
}