serialize-and-deserialize-bst

https://leetcode.com/problems/serialize-and-deserialize-bst/

1. 用到Java Queue接口，

// LinkedList实现了Queue接口, ArrayList没有实现

2. 用的Java String.split 函数得到 String数组。

3. 另外一个bug是因为String比较用的 == ，没有用 equals

package com.company;

import apple.laf.JRSUIUtils;

import java.util.*;

class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) { val = x; }
}

class Codec {
// Encodes a tree to a single string.
public String serialize(TreeNode root) {
StringBuilder sb = new StringBuilder();
if (root == null) {
return "";
}

// LinkedList实现了Queue接口, ArrayList没有实现
Queue<TreeNode> qe= new LinkedList<>();
qe.offer(root);
sb.append(root.val+",");
while (!qe.isEmpty()) {
TreeNode tn = qe.poll();
if (tn.left != null) {
sb.append(tn.left.val+",");
qe.offer(tn.left);
}
else {
sb.append(",");
}
if (tn.right != null) {
sb.append(tn.right.val+",");
qe.offer(tn.right);
}
else {
sb.append(",");
}
}
return sb.toString();
}

// Decodes your encoded data to tree.
public TreeNode deserialize(String data) {
if (data.equals("")) {
return null;
}

String[] strs = data.split(",");
Queue<TreeNode> qe = new LinkedList<>();

if (strs.length < 1 || strs[0].equals("")) {
return null;
}

TreeNode root = new TreeNode(Integer.valueOf(strs[0]));
qe.offer(root);
int i = 1;
while (!qe.isEmpty()) {
TreeNode tn = qe.poll();

if (strs.length > i && !strs[i].equals("")) {
TreeNode left = new TreeNode(Integer.valueOf(strs[i]));
tn.left = left;
qe.offer(left);
}
i++;
if (strs.length > i && !strs[i].equals("")) {
TreeNode right = new TreeNode(Integer.valueOf(strs[i]));
tn.right = right;
qe.offer(right);
}
i++;
}
return root;
}
}

public class Main {

public static void main(String[] args) throws InterruptedException {

System.out.println("Hello!");
//Solution solution = new Solution();

// Your Codec object will be instantiated and called as such:
TreeNode tn = new TreeNode(2);
TreeNode tn1 = new TreeNode(1);
//TreeNode tn2 = new TreeNode(3);
tn.left = tn1;
//tn.right = tn2;
Codec codec = new Codec();
String code = codec.serialize(tn);
System.out.printf("code:%s\n", code);
TreeNode ret = codec.deserialize(code);
System.out.printf("root:%d\n", ret.val);

System.out.println();

}
}