package jianzhioffer;
import java.util.Scanner;
import jianzhioffer.BinaryTree;
/**
* 请实现两个函数，分别用来序列化和反序列化二叉树
* 所谓序列化指的是遍历二叉树为字符串；所谓反序列化指的是依据字符串重新构造成二叉树。
*/
/* //树节点
public class TreeNode {
int val = 0;
TreeNode left = null;
TreeNode right = null;
public TreeNode(int val) {
this.val = val;
}
}
*/
public class Solution62 {
/*
* 依据前序遍历序列来序列化二叉树，因为前序遍历序列是从根结点开始的。当在遍历二叉树时碰到Null指针时，这些Null指针被序列化为一个特殊的字符“#”。
* 另外，结点之间的数值用逗号隔开。
*/
static int index = -1; //计数变量
static String Serialize(TreeNode root) {
StringBuffer sb = new StringBuffer();
if(root == null){
sb.append("#,");
return sb.toString();
}
sb.append(root.val + ",");
sb.append(Serialize(root.left));
sb.append(Serialize(root.right));
return sb.toString();
}
static TreeNode Deserialize(String str) {
index++;
int len = str.length();
if(index >= len){
return null;
}
String[] newstr = str.split(",");
TreeNode node = null;
if(!newstr[index].equals("#")){
node = new TreeNode(Integer.valueOf(newstr[index]));
node.left = Deserialize(str);
node.right = Deserialize(str);
}
return node;
}
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
TreeNode tree1 = new TreeNode(5);
TreeNode tree2 = new TreeNode(3);
TreeNode tree3 = new TreeNode(7);
TreeNode tree4 = new TreeNode(2);
TreeNode tree5 = new TreeNode(4);
TreeNode tree6 = new TreeNode(6);
TreeNode tree7 = new TreeNode(8);
tree1.left = tree2;
tree1.right = tree3;
tree2.left = tree4;
tree2.right = tree5;
tree3.left = tree6;
tree3.right = tree7;
System.out.println(Serialize(tree1));
BinaryTree bt = new BinaryTree();
System.out.println("反序列化二叉树的前序遍历结果：");
bt.preOrder(Deserialize(Serialize(tree1)));
}
}
