【树13】序列化二叉树

题目描述

请实现两个函数，分别用来序列化和反序列化二叉树

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

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

    }

}
*/
public class Solution {
    //前序遍历 序列化
    String Serialize(TreeNode root) {
        StringBuilder sb=new StringBuilder();
        //结点为空，以“#”代替
        if(root==null){
            sb.append("#,");
            return sb.toString();
        }
         //不为空，即以结点值赋值其后
        sb.append(root.val+","); 

        sb.append(Serialize(root.left)); 
        sb.append(Serialize(root.right)); 
        return sb.toString();
    }
    
    //反序列化，根据序列化后的字符串数组重建二叉树
    int index=-1;
    TreeNode Deserialize(String str) {
        index++;
        if(index>str.length())
            return null;
        String[] strArr=str.split(",");
        TreeNode node=null;
        if(!strArr[index].equals("#")){
            node=new TreeNode(Integer.valueOf(strArr[index]));
            node.left=Deserialize(str);
            node.right=Deserialize(str);
        }
        return node;
    }
    
    
    
    
}