剑指Offer-61 二叉树序列化

请实现两个函数，分别用来序列化和反序列化二叉树

利用广度遍历实现二叉树的序列化和非序列化。
核心思想：广度遍历

import java.util.*;
public class Solution {
      String Serialize(TreeNode root) {
        if(root == null) return "#,";
        StringBuilder builder = new StringBuilder();
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        while(!queue.isEmpty()){
            TreeNode node = queue.poll();
            if(node != null) {
                builder.append(node.val + ",");
                queue.offer(node.left);
                queue.offer(node.right);
            }
            else builder.append("#,");
        }
        return builder.toString();
    }
    TreeNode Deserialize(String str) {
        String[] strs = str.split(",");
        if(str.equals("") || strs[0].equals("#")) return null;
        TreeNode root = new TreeNode(Integer.valueOf(strs[0]));
        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);
        for(int i=1;i<strs.length;i++){
            TreeNode node = queue.poll();
            if(!strs[i].equals("#")){
                TreeNode left = new TreeNode(Integer.valueOf(strs[i]));
                node.left = left;
                queue.offer(left);
            }
            if(!strs[++i].equals("#")){
                TreeNode right = new TreeNode(Integer.valueOf(strs[i]));
                node.right = right;
                queue.offer(right);
            }
        }
        return root;
    }
}